Merge remote-tracking branch 'origin/main' into garrytan/dont-change-gstack-source

.github/workflows/pr-title-sync.yml

@@ -1,7 +1,25 @@
 name: PR Title Sync
 
+# WHY pull_request_target (not pull_request): the default GITHUB_TOKEN is
+# READ-ONLY on fork PRs under `pull_request`, so the title-sync backstop could
+# never `gh pr edit` a fork/agent PR. `pull_request_target` runs in the base-repo
+# context with a write token, which fixes fork coverage.
+#
+# WHY this is SAFE (pull_request_target is the most dangerous trigger):
+#   - We check out the BASE repo (no `ref:`), so the only code we execute is
+#     trusted base-repo infra (bin/gstack-pr-title-rewrite.sh). We NEVER check
+#     out or run PR-head/fork code.
+#   - Every attacker-controlled PR field (title, head repo, head sha) arrives via
+#     `env:` and is referenced as a shell-quoted "$VAR". We NEVER inline a
+#     `${{ github.event.pull_request.* }}` expression inside the run: script
+#     (that would execute a crafted title as shell).
+#   - The PR-head VERSION is read as DATA via the API (raw media type), from the
+#     head repo at the head sha — never by checking out the head.
+# test/pr-title-sync-workflow-safety.test.ts is the static tripwire for all of
+# the above and fails CI if any of it regresses.
+
 on:
-  pull_request:
+  pull_request_target:
     types: [opened, synchronize, edited]
     paths:
       - 'VERSION'
@@ -19,25 +37,62 @@ jobs:
       pull-requests: write
     if: github.actor != 'github-actions[bot]'
     steps:
-      - name: Checkout PR head
+      # Base repo only — trusted infra (the rewrite helper). No PR-head checkout.
+      - name: Checkout base repo (trusted)
         uses: actions/checkout@v4
         with:
           fetch-depth: 1
-          ref: ${{ github.event.pull_request.head.sha }}
 
       - name: Rewrite PR title to match VERSION
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           PR_NUM: ${{ github.event.pull_request.number }}
+          # Attacker-controlled on fork PRs — env-only, never inlined into run:.
           OLD_TITLE: ${{ github.event.pull_request.title }}
+          BASE_REPO: ${{ github.repository }}
+          HEAD_REPO: ${{ github.event.pull_request.head.repo.full_name }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
         run: |
           set -euo pipefail
           chmod +x ./bin/gstack-pr-title-rewrite.sh
-          VERSION=$(cat VERSION | tr -d '[:space:]')
-          NEW_TITLE=$(./bin/gstack-pr-title-rewrite.sh "$VERSION" "$OLD_TITLE")
-          if [ "$NEW_TITLE" = "$OLD_TITLE" ]; then
-            echo "Title already correct; no change."
+
+          if [ "$HEAD_REPO" = "$BASE_REPO" ]; then IS_FORK=0; else IS_FORK=1; fi
+
+          # Read the PR-head VERSION as data (raw bytes), from the head repo at
+          # the head sha. Guard the assignment itself: under `set -e` a bare
+          # `VERSION=$(...)` would abort the step before any later [ -z ] check.
+          if ! VERSION=$(gh api -H "Accept: application/vnd.github.raw" \
+              "repos/$HEAD_REPO/contents/VERSION?ref=$HEAD_SHA" 2>/dev/null | tr -d '[:space:]'); then
+            VERSION=""
+          fi
+
+          if [ -z "$VERSION" ]; then
+            # Same-repo read failure should never happen — fail loudly so we
+            # notice. A fork miss (public-contents quirk, private fork) is a
+            # convenience gap, not a gate — warn and skip so the check stays green.
+            if [ "$IS_FORK" = "0" ]; then
+              echo "::error::Could not read VERSION from same-repo PR head ($HEAD_SHA)."
+              exit 1
+            fi
+            echo "::warning::Could not read VERSION from fork $HEAD_REPO ($HEAD_SHA); skipping title sync."
+            exit 0
+          fi
+
+          # The helper rejects a malformed VERSION (exit 2). Same policy: loud for
+          # same-repo, soft for forks. Never echo the raw (attacker-controlled)
+          # title — Actions still parses ::workflow-command:: from stdout.
+          if ! NEW_TITLE=$(./bin/gstack-pr-title-rewrite.sh "$VERSION" "$OLD_TITLE"); then
+            if [ "$IS_FORK" = "0" ]; then
+              echo "::error::Could not compute title for VERSION '$VERSION' on PR #$PR_NUM."
+              exit 1
+            fi
+            echo "::warning::Could not compute title for fork PR #$PR_NUM; skipping."
+            exit 0
+          fi
+
+          if [ "$NEW_TITLE" = "$OLD_TITLE" ]; then
+            echo "PR #$PR_NUM title already correct; no change."
             exit 0
           fi
-          echo "Rewriting: $OLD_TITLE -> $NEW_TITLE"
           gh pr edit "$PR_NUM" --title "$NEW_TITLE"
+          echo "PR #$PR_NUM title synced to VERSION."

CHANGELOG.md

@@ -1,5 +1,183 @@
 # Changelog
 
+## [1.57.4.0] - 2026-06-08
+
+## **The completeness principle is now Boil the Ocean, matching the post it came from.**
+## **One name across the ETHOS file, every skill, and the developer-profile dial.**
+
+The principle that tells gstack to do the complete thing was called "Boil the Lake" in
+`ETHOS.md` and in every generated skill, with the ocean cast as the anti-pattern. The
+developer-profile system and the completeness intro link already used "boil the ocean"
+as the good, ship-the-whole-thing pole. So the same idea carried two opposite framings
+depending on where you read it. This renames the principle to Boil the Ocean everywhere
+and reframes the metaphor: the ocean is the complete destination, and lakes are the
+boilable units you ship on the way there. The guidance is identical. Only the name and
+the framing prose changed.
+
+### The numbers that matter
+
+Reproduce with `git diff v1.57.3.0..HEAD --stat`.
+
+| Property | Before | After |
+|---|---|---|
+| Principle name in ETHOS + every skill | "Boil the Lake" | "Boil the Ocean" |
+| Name vs. the `scope_appetite` dial ("boil the ocean" = complete) | split | unified |
+| Files updated | — | 63 (ETHOS, CLAUDE, README, resolvers, templates, generated SKILL.md) |
+| Runtime behavior change | — | none, text only |
+
+The one number that matters is zero: no behavior changed. A reviewer reading `ETHOS.md`
+no longer hits "ocean" as the thing to avoid in one section and the thing to aim for in
+the next.
+
+### What this means for you
+
+You get the same complete-the-work recommendations, now under the name from Garry's
+"Boil the Oceans" post. The metaphor reads straight through: the ocean is the goal,
+lakes are how you get there one boil at a time, and only genuinely unrelated
+multi-quarter migrations sit outside scope. Nothing to do on your end.
+
+### Itemized changes
+
+#### Changed
+- `ETHOS.md` section 1 is renamed to "Boil the Ocean" and reframed so the ocean is the
+  complete destination and lakes are the boilable first units, not the ceiling.
+- The "Completeness Principle" header injected into every tier-2+ skill now reads
+  "Boil the Ocean," with prose to match.
+- `CLAUDE.md` and `README.md` references updated to the new name.
+
+#### For contributors
+- Source of the rename lives in the preamble resolvers
+  (`generate-completeness-section.ts`, the `composition.ts` skip-list, and
+  `generate-lake-intro.ts`); all SKILL.md files are regenerated from them.
+- Unit assertions (`skill-validation`, `terse-build`) and the three ship golden
+  fixtures updated to the new header.
+
+## [1.57.3.0] - 2026-06-07
+
+## **Every PR `/ship` opens gets the version stamped into its title, fork and agent PRs included.**
+## **The rule rides in the always-loaded part of the skill now, and a guard keeps it there.**
+
+`/ship` stamps `vX.Y.Z.W` onto the title of every PR or MR it creates or updates, so
+the version is the first thing you read in the PR list. That rule now lives in the
+always-loaded core of the ship skill instead of an on-demand section, so the agent
+applies it whether or not it opened the section that spells out the full procedure.
+A CI workflow backs this up: it rewrites a title to match VERSION on every PR that
+bumps the version, and it now reaches fork and agent PRs too, which a read-only token
+could never touch before. Two free tests lock the behavior in so it cannot drift on
+the next refactor.
+
+### The numbers that matter
+
+Reproduce with `bun test test/carve-section-ordering.test.ts test/pr-title-sync-workflow-safety.test.ts`
+and `bun run eval:select`.
+
+| Property | Before | After |
+|---|---|---|
+| Where the title rule loads | on-demand section only (since v1.54.0.0) | always-loaded skeleton + on-demand detail |
+| Fork / agent PR title sync | none (read-only token under `pull_request`) | covered via hardened `pull_request_target` |
+| Test proving the rule stays put | none | carve-guard registry asserts it on every PR |
+| CI injection guard for the title workflow | none | static tripwire fails CI on unsafe patterns |
+
+The title workflow now runs with a write token in the base-repo context but never
+checks out or executes PR-head code, and every attacker-controlled field reaches the
+script through `env:`, never inlined. A static test fails CI if either rule regresses.
+
+### What this means for you
+
+Ship a branch and the PR shows up titled `v1.57.3.0 fix: ...` without you touching it,
+even when the PR came from a fork. The agent no longer needs to read the right section
+at the right moment for the version to land in the title, and the next person who slims
+the ship skill cannot quietly strand the rule again, because a free test on every PR
+checks that it is still there.
+
+### Itemized changes
+
+#### Added
+- Carve-guard coverage for the ship PR-title invariant: the registry now asserts the
+  `v$NEW_VERSION` rule and the title helper stay in the always-loaded skeleton, while
+  the full create and update procedure stays in the on-demand section.
+- Static CI-safety test for the title-sync workflow that fails the build if it checks
+  out PR-head code or inlines an attacker-controlled PR field into a shell step.
+
+#### Changed
+- The PR/MR title-version rule is always-loaded in `/ship` again, so the version
+  prefix lands on every PR the workflow creates or updates.
+- The PR title-sync CI workflow now covers fork and agent PRs through a hardened
+  `pull_request_target` trigger (base-repo checkout only, PR fields passed via `env:`,
+  VERSION read as data from the PR head).
+
+#### Fixed
+- A path token in the ship PR-body section that rendered literally instead of resolving
+  now uses the correct helper path, so the Linked Spec auto-detect step runs as written.
+
+## [1.57.2.0] - 2026-06-08
+
+## **When the question picker breaks mid-skill, gstack asks in plain text instead of stalling.**
+## **Every skill detects a dead AskUserQuestion and falls back to a full decision brief you answer by typing a letter.**
+
+AskUserQuestion is how every gstack skill asks you to decide. When the host's question
+tool fails at runtime, which Conductor's MCP integration currently does intermittently,
+skills used to stall or hard-block. Now each skill detects the failure, works out
+whether a human is actually present, and if so re-renders the exact same decision as a
+text message: a plain-English explanation of the issue, a completeness score on each
+choice, and a recommendation with its reason, one paragraph per choice. You answer by
+typing a single letter. Headless eval runs still block cleanly (no human to answer);
+orchestrator sessions keep auto-choosing. This whole release was built and reviewed
+through that fallback, because the Conductor tool was down the entire session.
+
+### The numbers that matter
+
+No production benchmark for a reliability path like this. These are the behavior and
+coverage facts, verifiable with `bun test test/gstack-session-kind.test.ts
+test/resolver-ask-user-format.test.ts test/auq-error-fallback-hook.test.ts`.
+
+| When AskUserQuestion fails | Before | After |
+|---|---|---|
+| Interactive session (human present) | stall / hard BLOCK | full prose decision brief, answer by letter |
+| Headless eval / CI | BLOCK | BLOCK (unchanged, correct) |
+| Orchestrator (OpenClaw) session | undefined | auto-choose recommended (contract kept) |
+| Session kinds detected | 0 | 3 (interactive / headless / spawned) |
+| New tests guarding the path | 0 | 34 |
+
+The text brief is not a degraded stub. It carries the same three things the picker
+shows: a clear explanation of what is being decided, a `Completeness: X/10` on every
+choice, and a recommendation with the reason it wins.
+
+### What this means for you
+
+If your host's question tool flakes out, a skill no longer dies on you. You get the
+same decision to make, in text, and you reply with a letter. Nothing changes when the
+tool works normally. If you run gstack headless, those sessions still block on a needed
+question exactly as before, so eval determinism is intact.
+
+### Itemized changes
+
+#### Added
+- `gstack-session-kind` classifies each session as interactive, headless, or spawned,
+  echoed as `SESSION_KIND` at skill start so any skill can branch on it.
+- Plain-text fallback for AskUserQuestion: on a tool failure in an interactive session,
+  the skill renders the full decision brief (issue ELI10 + per-choice completeness +
+  recommendation) as markdown you answer by typing a letter, then stops and waits.
+- A defensive hook that, when an AskUserQuestion call errors, reminds the agent to run
+  the fallback for the current session kind.
+
+#### Changed
+- AskUserQuestion is still sent as a normal tool call; the prose path applies only when
+  the tool is unavailable or erroring, and never on a `[plan-tune auto-decide]` result.
+
+#### Fixed
+- Section-loading tests use the canonical kebab test names, so the test-coverage gate
+  matches them.
+- External-host doc-freshness checks are deterministic, no longer dependent on a prior
+  full regeneration.
+
+#### For contributors
+- The eval/E2E runners set `GSTACK_HEADLESS=1` so headless runs classify correctly;
+  interactive-path suites opt out per-run.
+- Per-skill `maxSizeRatio` override in the carve-guards registry; `document-release`
+  gets 1.08 headroom for the cross-cutting preamble addition while every other skill
+  keeps the 1.05 ceiling.
+
 ## [1.57.0.0] - 2026-06-07
 
 ## **Three more heavyweight skills load lighter, and every carved skill finally has a test that proves it loads.**

CLAUDE.md

@@ -137,7 +137,7 @@ gstack/
 ├── setup            # One-time setup: build binary + symlink skills
 ├── SKILL.md         # Generated from SKILL.md.tmpl (don't edit directly)
 ├── SKILL.md.tmpl    # Template: edit this, run gen:skill-docs
-├── ETHOS.md         # Builder philosophy (Boil the Lake, Search Before Building)
+├── ETHOS.md         # Builder philosophy (Boil the Ocean, Search Before Building)
 └── package.json     # Build scripts for browse
 ```
 
@@ -776,8 +776,10 @@ When estimating or discussing effort, always show both human-team and CC+gstack
 | Research / exploration | 1 day | 3 hours | ~3x |
 
 Completeness is cheap. Don't recommend shortcuts when the complete implementation
-is a "lake" (achievable) not an "ocean" (multi-quarter migration). See the
-Completeness Principle in the skill preamble for the full philosophy.
+is achievable. Boil the ocean — the complete thing is the goal; only genuinely
+unrelated multi-quarter migrations are separate scope, never an excuse for a
+shortcut. See the Completeness Principle in the skill preamble for the full
+philosophy.
 
 ## Search before building
 

ETHOS.md

@@ -31,16 +31,21 @@ The last 10% of completeness that teams used to skip? It costs seconds now.
 
 ---
 
-## 1. Boil the Lake
+## 1. Boil the Ocean
 
-AI-assisted coding makes the marginal cost of completeness near-zero. When
-the complete implementation costs minutes more than the shortcut — do the
+"Don't boil the ocean" was the right advice when engineering time was the
+bottleneck. That era is over. AI-assisted coding makes the marginal cost of
+completeness near-zero, so the old caution has quietly turned into an excuse.
+When the complete implementation costs minutes more than the shortcut — do the
 complete thing. Every time.
 
-**Lake vs. ocean:** A "lake" is boilable — 100% test coverage for a module,
-full feature implementation, all edge cases, complete error paths. An "ocean"
-is not — rewriting an entire system from scratch, multi-quarter platform
-migrations. Boil lakes. Flag oceans as out of scope.
+**Ocean, lakes first:** The ocean is the destination — 100% test coverage for a
+module, full feature implementation, all edge cases, complete error paths. You
+get there one lake at a time: each lake is a boilable unit, not the ceiling.
+"That's boiling the ocean" is no longer a reason to ship a shortcut — boiling
+the ocean is the goal. The only thing still out of scope is genuinely unrelated
+work: a multi-quarter platform migration that has nothing to do with the task at
+hand. Flag that as separate scope. Boil everything else.
 
 **Completeness is cheap.** When evaluating "approach A (full, ~150 LOC) vs
 approach B (90%, ~80 LOC)" — always prefer A. The 70-line delta costs
@@ -144,7 +149,7 @@ think it's better, state what context you might be missing, and ask. Never act.
 
 ## How They Work Together
 
-Boil the Lake says: **do the complete thing.**
+Boil the Ocean says: **do the complete thing.**
 Search Before Building says: **know what exists before you decide what to build.**
 
 Together: search first, then build the complete version of the right thing.

README.md

@@ -429,7 +429,7 @@ Other references: [docs/gbrain-sync.md](docs/gbrain-sync.md) (sync-specific guid
 | Doc | What it covers |
 |-----|---------------|
 | [Skill Deep Dives](docs/skills.md) | Philosophy, examples, and workflow for every skill (includes Greptile integration) |
-| [Builder Ethos](ETHOS.md) | Builder philosophy: Boil the Lake, Search Before Building, three layers of knowledge |
+| [Builder Ethos](ETHOS.md) | Builder philosophy: Boil the Ocean, Search Before Building, three layers of knowledge |
 | [Using GBrain with GStack](USING_GBRAIN_WITH_GSTACK.md) | Every path, flag, bin helper, and troubleshooting step for `/setup-gbrain` |
 | [GBrain Sync](docs/gbrain-sync.md) | Cross-machine memory setup, privacy modes, troubleshooting |
 | [Architecture](ARCHITECTURE.md) | Design decisions and system internals |

SKILL.md

@@ -45,6 +45,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -124,7 +127,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -159,7 +162,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

VERSION

@@ -1 +1 @@
-1.57.0.0
+1.57.4.0

autoplan/SKILL.md

@@ -54,6 +54,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -133,7 +136,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -168,7 +171,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -305,11 +308,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -389,7 +412,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -596,9 +619,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -802,7 +825,7 @@ Read the `/office-hours` skill file at `~/.claude/skills/gstack/office-hours/SKI
 Follow its instructions from top to bottom, **skipping these sections** (already handled by the parent skill):
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Contributor Mode
 - Completion Status Protocol
@@ -1008,7 +1031,7 @@ Read each file using the Read tool:
 (they are already handled by /autoplan):**
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Completion Status Protocol
 - Telemetry (run last)

autoplan/SKILL.md.tmpl

@@ -216,7 +216,7 @@ Read each file using the Read tool:
 (they are already handled by /autoplan):**
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Completion Status Protocol
 - Telemetry (run last)

benchmark-models/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

benchmark/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

bin/gstack-session-kind

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+# gstack-session-kind — classify the current agent session so skills know whether
+# a human can answer an interactive prompt (AskUserQuestion).
+#
+# Usage: gstack-session-kind            → prints one of: spawned | headless | interactive
+#
+# Used by the preamble (generate-preamble-bash.ts) which echoes
+#   SESSION_KIND: <value>
+# so the AskUserQuestion-failure fallback rule can branch without a shell-out at
+# failure time:
+#   spawned     → orchestrator session (OpenClaw). Auto-choose recommended option
+#                 per the skill's SPAWNED_SESSION block. Never prose, never BLOCKED.
+#   headless    → no human present (claude -p evals / CI). BLOCK on AUQ failure.
+#   interactive → a human is present. Prose-fallback on AUQ failure.
+#
+# Detection is best-effort. On ANY ambiguity it prints `interactive` — BLOCK only on
+# a positive headless signal, since a stray prose message in an unmarked one-shot
+# `-p` run just ends the turn (harmless), whereas wrongly BLOCKING a real human is not.
+#
+# Why env vars and not TTY/entrypoint: an interactive Conductor session reports
+# CLAUDE_CODE_ENTRYPOINT=sdk-ts with no TTY — identical to a headless SDK eval. The
+# signals that actually discriminate are the host/orchestrator/CI env markers below.
+set -euo pipefail
+
+# 1. Orchestrator-spawned session (OpenClaw). Authoritative block lives in the skill;
+#    we only surface the classification.
+if [ -n "${OPENCLAW_SESSION:-}" ]; then
+  echo "spawned"
+  exit 0
+fi
+
+# 2. Explicit headless override (set by the eval/E2E harness for determinism).
+if [ -n "${GSTACK_HEADLESS:-}" ]; then
+  echo "headless"
+  exit 0
+fi
+
+# 3. Positive interactive-host signals: a human-driven host is present.
+#    - Conductor app sets CONDUCTOR_* workspace vars.
+#    - Plain interactive `claude` CLI sets CLAUDE_CODE_ENTRYPOINT=cli.
+if [ -n "${CONDUCTOR_WORKSPACE_PATH:-}" ] || [ -n "${CONDUCTOR_PORT:-}" ] || [ "${CLAUDE_CODE_ENTRYPOINT:-}" = "cli" ]; then
+  echo "interactive"
+  exit 0
+fi
+
+# 4. CI / automation markers with no interactive host → headless.
+if [ -n "${CI:-}" ] || [ -n "${GITHUB_ACTIONS:-}" ]; then
+  echo "headless"
+  exit 0
+fi
+
+# 5. No positive headless signal → assume a human is present (degrade-safe default).
+echo "interactive"

browse/SKILL.md

@@ -46,6 +46,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -125,7 +128,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -160,7 +163,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

canary/SKILL.md

@@ -46,6 +46,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -125,7 +128,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -160,7 +163,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -297,11 +300,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -381,7 +404,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -588,9 +611,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

codex/SKILL.md

@@ -49,6 +49,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -128,7 +131,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -163,7 +166,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -300,11 +303,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -384,7 +407,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -591,9 +614,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

context-restore/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

context-save/SKILL.md

@@ -49,6 +49,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -128,7 +131,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -163,7 +166,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -300,11 +303,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -384,7 +407,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -591,9 +614,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

cso/SKILL.md

@@ -52,6 +52,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -131,7 +134,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -166,7 +169,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -303,11 +306,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -387,7 +410,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -594,9 +617,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

design-consultation/SKILL.md

@@ -72,6 +72,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -151,7 +154,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -186,7 +189,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -323,11 +326,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -407,7 +430,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -614,9 +637,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

design-html/SKILL.md

@@ -53,6 +53,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -132,7 +135,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -167,7 +170,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -304,11 +307,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -388,7 +411,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -595,9 +618,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

design-review/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

design-shotgun/SKILL.md

@@ -67,6 +67,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -146,7 +149,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -181,7 +184,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -318,11 +321,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -402,7 +425,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -609,9 +632,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

devex-review/SKILL.md

@@ -52,6 +52,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -131,7 +134,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -166,7 +169,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -303,11 +306,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -387,7 +410,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -594,9 +617,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

docs/spikes/claude-code-hook-mutation.md

@@ -127,6 +127,38 @@ required for our hook to fire there.
 (PostToolUse hooks can also set `additionalContext` to append to the tool
 result; we don't need this for v1 capture.)
 
+## PostToolUse on tool error (AUQ-failure fallback, OV3:B) — UNVERIFIED
+
+The AUQ-failure prose fallback adds a defensive PostToolUse hook
+(`hosts/claude/hooks/auq-error-fallback-hook.ts`) that, when an AskUserQuestion
+call returns an error / missing result, injects `additionalContext` reminding the
+model to run the prose fallback per `SESSION_KIND`. It uses the same
+`additionalContext` mechanism documented above.
+
+**Open question we could NOT settle in a harness:** does Claude Code invoke
+PostToolUse hooks when an MCP tool call returns a transport/missing-result error
+(the Conductor bug surfaces `[Tool result missing due to internal error]`)? The
+docs above cover PostToolUse on *success*. We could not force the Conductor
+internal MCP failure on demand to observe it.
+
+**Decision (OV3:B = A):** build the hook defensively anyway.
+- It is **inert on success** (only fires when `isErrorResponse(tool_response)` is
+  true) and **inert if the platform never invokes it** on the error path.
+- The prompt-level fallback in `generate-ask-user-format.ts` covers the case
+  regardless — the hook is a reliability *layer*, not the mechanism.
+- Its decision logic is unit-tested deterministically
+  (`test/auq-error-fallback-hook.test.ts`): given a synthetic error `tool_response`
+  + each `SESSION_KIND`, it emits the correct directive; given a real answer it
+  defers.
+
+**Recommended manual / partial spike (to close the gap later):** register a
+throwaway PostToolUse hook that logs on fire, then (a) trigger a normal tool
+error (e.g. a failing `Bash` call) to confirm PostToolUse fires on tool errors at
+all, and (b) reproduce the Conductor MCP AUQ failure and check the log. If (b)
+confirms a fire, promote the hook from "defensive/inert" to "verified". Until
+then, treat the runtime layer as best-effort and the prompt-level fallback as the
+guaranteed path.
+
 ## Settings.json snippet for T8 hook installer
 
 ```json

document-generate/SKILL.md

@@ -52,6 +52,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -131,7 +134,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -166,7 +169,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -303,11 +306,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -387,7 +410,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -594,9 +617,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -1177,4 +1200,4 @@ Documentation generated:
 - **Voice: friendly, concrete, user-forward.** Write like you're explaining to a smart person
   who hasn't seen the code. Never corporate, never academic.
 - **Completeness over minimalism.** AI makes comprehensive documentation cheap. Don't write
-  "minimal viable docs" — write complete docs. Boil the lake.
+  "minimal viable docs" — write complete docs. Boil the ocean.

document-generate/SKILL.md.tmpl

@@ -457,4 +457,4 @@ Documentation generated:
 - **Voice: friendly, concrete, user-forward.** Write like you're explaining to a smart person
   who hasn't seen the code. Never corporate, never academic.
 - **Completeness over minimalism.** AI makes comprehensive documentation cheap. Don't write
-  "minimal viable docs" — write complete docs. Boil the lake.
+  "minimal viable docs" — write complete docs. Boil the ocean.

document-release/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

health/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -299,11 +302,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -383,7 +406,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -590,9 +613,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

hosts/claude/hooks/auq-error-fallback-hook

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Bash shim — Claude Code hooks run `command` strings via /bin/sh, so this
+# wrapper makes the TypeScript hook executable via bun. Settings.json
+# references this file directly.
+set -e
+HERE="$(cd "$(dirname "$0")" && pwd)"
+exec bun "$HERE/auq-error-fallback-hook.ts"

hosts/claude/hooks/auq-error-fallback-hook.ts

@@ -0,0 +1,202 @@
+#!/usr/bin/env bun
+/**
+ * PostToolUse hook for AskUserQuestion — runtime reliability layer for the
+ * AUQ-failure prose fallback (OV3:B).
+ *
+ * When an AskUserQuestion call comes back as an ERROR / missing result (the
+ * Conductor MCP bug returns `[Tool result missing due to internal error]`), this
+ * hook injects `additionalContext` reminding the model of the failure-fallback
+ * rule, tailored to the session kind. It does NOT render the prose itself — the
+ * model still emits it. The hook only guarantees the reminder fires at the moment
+ * of failure, instead of relying on the model noticing the error result and
+ * recalling the echoed SESSION_KIND.
+ *
+ * DEFENSIVE / INERT-IF-UNSUPPORTED: it is unverified whether Claude Code invokes
+ * PostToolUse hooks when an MCP tool returns a transport/missing-result error (we
+ * could not force that Conductor-internal failure in a harness — see
+ * docs/spikes/claude-code-hook-mutation.md §"PostToolUse on tool error"). If the
+ * platform does NOT fire the hook on that path, this is simply never invoked — no
+ * harm; the prompt-level fallback in generate-ask-user-format.ts still covers it.
+ * On a SUCCESSFUL AskUserQuestion (a real answer), the hook defers (no output).
+ *
+ * Triggered by ~/.claude/settings.json (registered by `setup` next to
+ * question-log-hook):
+ *   PostToolUse matcher "(AskUserQuestion|mcp__.*__AskUserQuestion)"
+ *
+ * Invariants:
+ *   - Always exits 0. A failing hook MUST NOT block the user's session.
+ *   - Never triggers on a successful answer (would corrupt a normal AUQ).
+ *   - Errors land in ~/.gstack/hook-errors.log.
+ */
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+import { spawnSync } from 'child_process';
+
+interface HookStdin {
+  tool_name?: string;
+  tool_response?: unknown;
+  cwd?: string;
+}
+
+function stateRoot(): string {
+  return (
+    process.env.GSTACK_STATE_ROOT ||
+    process.env.GSTACK_HOME ||
+    path.join(os.homedir(), '.gstack')
+  );
+}
+
+function logHookError(msg: string): void {
+  try {
+    const sr = stateRoot();
+    fs.mkdirSync(sr, { recursive: true });
+    fs.appendFileSync(
+      path.join(sr, 'hook-errors.log'),
+      `${new Date().toISOString()} auq-error-fallback-hook: ${msg}\n`,
+    );
+  } catch {
+    // last-resort swallow
+  }
+}
+
+function readStdin(): Promise<string> {
+  return new Promise((resolve) => {
+    let buf = '';
+    process.stdin.setEncoding('utf-8');
+    process.stdin.on('data', (chunk) => (buf += chunk));
+    process.stdin.on('end', () => resolve(buf));
+    process.stdin.on('error', () => resolve(buf));
+    setTimeout(() => resolve(buf), 2000);
+  });
+}
+
+/** No-op output — let the tool result stand untouched. */
+function defer(): void {
+  process.stdout.write(
+    JSON.stringify({ hookSpecificOutput: { hookEventName: 'PostToolUse' } }),
+  );
+  process.exit(0);
+}
+
+function inject(additionalContext: string): void {
+  process.stdout.write(
+    JSON.stringify({
+      hookSpecificOutput: { hookEventName: 'PostToolUse', additionalContext },
+    }),
+  );
+  process.exit(0);
+}
+
+/**
+ * Decide whether the tool_response is an ERROR / missing result rather than a
+ * real answer. Conservative: only flag clear failure shapes, so a successful
+ * AskUserQuestion (which carries the user's choice) is never misread as failure.
+ */
+export function isErrorResponse(response: unknown): boolean {
+  if (response === null || response === undefined) return true;
+  if (typeof response === 'string') {
+    const s = response.trim();
+    if (s === '') return true;
+    // Match ONLY the specific missing-result sentinel phrase, not any string that
+    // merely contains "error" — a real answer like "Investigate the internal error"
+    // must NOT trigger the fallback. (Codex review finding.)
+    return /tool result missing/i.test(s);
+  }
+  if (typeof response === 'object') {
+    const rec = response as Record<string, unknown>;
+    // Structured flag must be the boolean true — not the substring "is_error" inside
+    // a serialized success payload like '{"is_error": false}'.
+    if (rec.is_error === true || rec.isError === true) return true;
+    if (typeof rec.error === 'string' && rec.error.trim() !== '') return true;
+    // Some hosts wrap the payload as { content: "..." } or { content: [{text}] }.
+    const content = rec.content;
+    if (typeof content === 'string') return /tool result missing/i.test(content);
+    if (Array.isArray(content)) {
+      const text = content
+        .map((c) => (typeof c === 'string' ? c : (c as Record<string, unknown>)?.text ?? ''))
+        .join(' ');
+      return /tool result missing/i.test(text);
+    }
+  }
+  return false;
+}
+
+/** Resolve SESSION_KIND via the shared helper (same classification the preamble
+ *  echoes). Falls back to 'interactive' (degrade-safe) on any failure. */
+export function sessionKind(cwd?: string): 'spawned' | 'headless' | 'interactive' {
+  try {
+    const here = path.dirname(new URL(import.meta.url).pathname);
+    const bin = path.resolve(here, '..', '..', '..', 'bin', 'gstack-session-kind');
+    const res = spawnSync(bin, [], {
+      encoding: 'utf-8',
+      timeout: 3000,
+      cwd: cwd && fs.existsSync(cwd) ? cwd : undefined,
+    });
+    const out = (res.stdout || '').trim();
+    if (out === 'spawned' || out === 'headless' || out === 'interactive') return out;
+  } catch (e) {
+    logHookError(`sessionKind failed: ${(e as Error).message}`);
+  }
+  return 'interactive';
+}
+
+/** The directive injected per session kind. Exported for unit testing. */
+export function directiveFor(kind: 'spawned' | 'headless' | 'interactive'): string {
+  const lead =
+    'The AskUserQuestion call did not return a usable answer (error / missing result). ' +
+    'Per the AskUserQuestion failure-fallback rule: ';
+  switch (kind) {
+    case 'spawned':
+      return (
+        lead +
+        'SESSION_KIND=spawned — auto-choose the recommended option per the Spawned session block. ' +
+        'Do not emit prose, do not BLOCK.'
+      );
+    case 'headless':
+      return (
+        lead +
+        'SESSION_KIND=headless — report `BLOCKED — AskUserQuestion unavailable` and stop; no human can answer.'
+      );
+    case 'interactive':
+    default:
+      return (
+        lead +
+        'SESSION_KIND=interactive — render the decision as a PROSE message now: a clear ELI10 of the issue, ' +
+        'then a Recommendation line, then ONE paragraph per choice carrying its `(recommended)` marker, its ' +
+        '`Completeness: X/10`, and 2-4 sentences of reasoning. Tell the user to reply with a letter, then STOP. ' +
+        '(Retry the call once first only if no answer could have surfaced.)'
+      );
+  }
+}
+
+async function main(): Promise<void> {
+  const raw = await readStdin();
+  if (!raw.trim()) return defer();
+
+  let stdin: HookStdin;
+  try {
+    stdin = JSON.parse(raw);
+  } catch (e) {
+    logHookError(`stdin parse failed: ${(e as Error).message}`);
+    return defer();
+  }
+
+  const toolName = stdin.tool_name || '';
+  if (toolName !== 'AskUserQuestion' && !/^mcp__.+__AskUserQuestion$/.test(toolName)) {
+    return defer();
+  }
+
+  if (!isErrorResponse(stdin.tool_response)) return defer();
+
+  inject(directiveFor(sessionKind(stdin.cwd)));
+}
+
+// Only run the stdin→stdout pipeline when executed as a hook, not when imported
+// by the unit test (which exercises the exported pure functions).
+if (import.meta.main) {
+  main().catch((e) => {
+    logHookError(`main crash: ${(e as Error).message}`);
+    defer();
+  });
+}

investigate/SKILL.md

@@ -87,6 +87,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -166,7 +169,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -201,7 +204,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -338,11 +341,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -422,7 +445,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -629,9 +652,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ios-clean/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ios-design-review/SKILL.md

@@ -52,6 +52,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -131,7 +134,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -166,7 +169,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -303,11 +306,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -387,7 +410,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -594,9 +617,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ios-fix/SKILL.md

@@ -53,6 +53,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -132,7 +135,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -167,7 +170,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -304,11 +307,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -388,7 +411,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -595,9 +618,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ios-qa/SKILL.md

@@ -56,6 +56,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -135,7 +138,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -170,7 +173,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -307,11 +310,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -391,7 +414,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -598,9 +621,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ios-sync/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

land-and-deploy/SKILL.md

@@ -45,6 +45,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -124,7 +127,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -159,7 +162,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -296,11 +299,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -380,7 +403,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -587,9 +610,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

landing-report/SKILL.md

@@ -46,6 +46,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -125,7 +128,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -160,7 +163,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -297,11 +300,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -381,7 +404,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -588,9 +611,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

learn/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -299,11 +302,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -383,7 +406,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -590,9 +613,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

make-pdf/SKILL.md

@@ -47,6 +47,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -162,7 +165,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -197,7 +200,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

office-hours/SKILL.md

@@ -83,6 +83,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -162,7 +165,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -197,7 +200,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -334,11 +337,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -418,7 +441,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -625,9 +648,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

open-gstack-browser/SKILL.md

@@ -45,6 +45,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -124,7 +127,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -159,7 +162,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -296,11 +299,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -380,7 +403,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -587,9 +610,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.57.0.0",
+  "version": "1.57.4.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",

pair-agent/SKILL.md

@@ -47,6 +47,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -126,7 +129,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -161,7 +164,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -298,11 +301,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -382,7 +405,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -589,9 +612,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

plan-ceo-review/SKILL.md

@@ -77,6 +77,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -156,7 +159,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -191,7 +194,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -328,11 +331,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -412,7 +435,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -619,9 +642,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -803,7 +826,7 @@ But your posture depends on what the user needs:
 * SELECTIVE EXPANSION: You are a rigorous reviewer who also has taste. Hold the current scope as your baseline — make it bulletproof. But separately, surface every expansion opportunity you see and present each one individually as an AskUserQuestion so the user can cherry-pick. Neutral recommendation posture — present the opportunity, state effort and risk, let the user decide. Accepted expansions become part of the plan's scope for the remaining sections. Rejected ones go to "NOT in scope."
 * HOLD SCOPE: You are a rigorous reviewer. The plan's scope is accepted. Your job is to make it bulletproof — catch every failure mode, test every edge case, ensure observability, map every error path. Do not silently reduce OR expand.
 * SCOPE REDUCTION: You are a surgeon. Find the minimum viable version that achieves the core outcome. Cut everything else. Be ruthless.
-* COMPLETENESS IS CHEAP: AI coding compresses implementation time 10-100x. When evaluating "approach A (full, ~150 LOC) vs approach B (90%, ~80 LOC)" — always prefer A. The 70-line delta costs seconds with CC. "Ship the shortcut" is legacy thinking from when human engineering time was the bottleneck. Boil the lake.
+* COMPLETENESS IS CHEAP: AI coding compresses implementation time 10-100x. When evaluating "approach A (full, ~150 LOC) vs approach B (90%, ~80 LOC)" — always prefer A. The 70-line delta costs seconds with CC. "Ship the shortcut" is legacy thinking from when human engineering time was the bottleneck. Boil the ocean.
 Critical rule: In ALL modes, the user is 100% in control. Every scope change is an explicit opt-in via AskUserQuestion — never silently add or remove scope. Once the user selects a mode, COMMIT to it. Do not silently drift toward a different mode. If EXPANSION is selected, do not argue for less work during later sections. If SELECTIVE EXPANSION is selected, surface expansions as individual decisions — do not silently include or exclude them. If REDUCTION is selected, do not sneak scope back in. Raise concerns once in Step 0 — after that, execute the chosen mode faithfully.
 Do NOT make any code changes. Do NOT start implementation. Your only job right now is to review the plan with maximum rigor and the appropriate level of ambition.
 
@@ -930,7 +953,7 @@ Read the `/office-hours` skill file at `~/.claude/skills/gstack/office-hours/SKI
 Follow its instructions from top to bottom, **skipping these sections** (already handled by the parent skill):
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Contributor Mode
 - Completion Status Protocol
@@ -976,7 +999,7 @@ Read the `/office-hours` skill file at `~/.claude/skills/gstack/office-hours/SKI
 Follow its instructions from top to bottom, **skipping these sections** (already handled by the parent skill):
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Contributor Mode
 - Completion Status Protocol

plan-ceo-review/SKILL.md.tmpl

@@ -64,7 +64,7 @@ But your posture depends on what the user needs:
 * SELECTIVE EXPANSION: You are a rigorous reviewer who also has taste. Hold the current scope as your baseline — make it bulletproof. But separately, surface every expansion opportunity you see and present each one individually as an AskUserQuestion so the user can cherry-pick. Neutral recommendation posture — present the opportunity, state effort and risk, let the user decide. Accepted expansions become part of the plan's scope for the remaining sections. Rejected ones go to "NOT in scope."
 * HOLD SCOPE: You are a rigorous reviewer. The plan's scope is accepted. Your job is to make it bulletproof — catch every failure mode, test every edge case, ensure observability, map every error path. Do not silently reduce OR expand.
 * SCOPE REDUCTION: You are a surgeon. Find the minimum viable version that achieves the core outcome. Cut everything else. Be ruthless.
-* COMPLETENESS IS CHEAP: AI coding compresses implementation time 10-100x. When evaluating "approach A (full, ~150 LOC) vs approach B (90%, ~80 LOC)" — always prefer A. The 70-line delta costs seconds with CC. "Ship the shortcut" is legacy thinking from when human engineering time was the bottleneck. Boil the lake.
+* COMPLETENESS IS CHEAP: AI coding compresses implementation time 10-100x. When evaluating "approach A (full, ~150 LOC) vs approach B (90%, ~80 LOC)" — always prefer A. The 70-line delta costs seconds with CC. "Ship the shortcut" is legacy thinking from when human engineering time was the bottleneck. Boil the ocean.
 Critical rule: In ALL modes, the user is 100% in control. Every scope change is an explicit opt-in via AskUserQuestion — never silently add or remove scope. Once the user selects a mode, COMMIT to it. Do not silently drift toward a different mode. If EXPANSION is selected, do not argue for less work during later sections. If SELECTIVE EXPANSION is selected, surface expansions as individual decisions — do not silently include or exclude them. If REDUCTION is selected, do not sneak scope back in. Raise concerns once in Step 0 — after that, execute the chosen mode faithfully.
 Do NOT make any code changes. Do NOT start implementation. Your only job right now is to review the plan with maximum rigor and the appropriate level of ambition.
 

plan-design-review/SKILL.md

@@ -49,6 +49,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -128,7 +131,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -163,7 +166,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -300,11 +303,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -384,7 +407,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -591,9 +614,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

plan-devex-review/SKILL.md

@@ -55,6 +55,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -134,7 +137,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -169,7 +172,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -306,11 +309,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -390,7 +413,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -597,9 +620,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -943,7 +966,7 @@ Read the `/office-hours` skill file at `~/.claude/skills/gstack/office-hours/SKI
 Follow its instructions from top to bottom, **skipping these sections** (already handled by the parent skill):
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Contributor Mode
 - Completion Status Protocol

plan-eng-review/SKILL.md

@@ -53,6 +53,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -132,7 +135,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -167,7 +170,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -304,11 +307,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -388,7 +411,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -595,9 +618,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -863,7 +886,7 @@ Read the `/office-hours` skill file at `~/.claude/skills/gstack/office-hours/SKI
 Follow its instructions from top to bottom, **skipping these sections** (already handled by the parent skill):
 - Preamble (run first)
 - AskUserQuestion Format
-- Completeness Principle — Boil the Lake
+- Completeness Principle — Boil the Ocean
 - Search Before Building
 - Contributor Mode
 - Completion Status Protocol
@@ -904,7 +927,7 @@ Before reviewing anything, answer these questions:
    If the plan rolls a custom solution where a built-in exists, flag it as a scope reduction opportunity. Annotate recommendations with **[Layer 1]**, **[Layer 2]**, **[Layer 3]**, or **[EUREKA]** (see preamble's Search Before Building section). If you find a eureka moment — a reason the standard approach is wrong for this case — present it as an architectural insight.
 5. **TODOS cross-reference:** Read `TODOS.md` if it exists. Are any deferred items blocking this plan? Can any deferred items be bundled into this PR without expanding scope? Does this plan create new work that should be captured as a TODO?
 
-5. **Completeness check:** Is the plan doing the complete version or a shortcut? With AI-assisted coding, the cost of completeness (100% test coverage, full edge case handling, complete error paths) is 10-100x cheaper than with a human team. If the plan proposes a shortcut that saves human-hours but only saves minutes with CC+gstack, recommend the complete version. Boil the lake.
+5. **Completeness check:** Is the plan doing the complete version or a shortcut? With AI-assisted coding, the cost of completeness (100% test coverage, full edge case handling, complete error paths) is 10-100x cheaper than with a human team. If the plan proposes a shortcut that saves human-hours but only saves minutes with CC+gstack, recommend the complete version. Boil the ocean.
 
 6. **Distribution check:** If the plan introduces a new artifact type (CLI binary, library package, container image, mobile app), does it include the build/publish pipeline? Code without distribution is code nobody can use. Check:
    - Is there a CI/CD workflow for building and publishing the artifact?

plan-eng-review/SKILL.md.tmpl

@@ -112,7 +112,7 @@ Before reviewing anything, answer these questions:
    If the plan rolls a custom solution where a built-in exists, flag it as a scope reduction opportunity. Annotate recommendations with **[Layer 1]**, **[Layer 2]**, **[Layer 3]**, or **[EUREKA]** (see preamble's Search Before Building section). If you find a eureka moment — a reason the standard approach is wrong for this case — present it as an architectural insight.
 5. **TODOS cross-reference:** Read `TODOS.md` if it exists. Are any deferred items blocking this plan? Can any deferred items be bundled into this PR without expanding scope? Does this plan create new work that should be captured as a TODO?
 
-5. **Completeness check:** Is the plan doing the complete version or a shortcut? With AI-assisted coding, the cost of completeness (100% test coverage, full edge case handling, complete error paths) is 10-100x cheaper than with a human team. If the plan proposes a shortcut that saves human-hours but only saves minutes with CC+gstack, recommend the complete version. Boil the lake.
+5. **Completeness check:** Is the plan doing the complete version or a shortcut? With AI-assisted coding, the cost of completeness (100% test coverage, full edge case handling, complete error paths) is 10-100x cheaper than with a human team. If the plan proposes a shortcut that saves human-hours but only saves minutes with CC+gstack, recommend the complete version. Boil the ocean.
 
 6. **Distribution check:** If the plan introduces a new artifact type (CLI binary, library package, container image, mobile app), does it include the build/publish pipeline? Code without distribution is code nobody can use. Check:
    - Is there a CI/CD workflow for building and publishing the artifact?

plan-tune/SKILL.md

@@ -58,6 +58,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -137,7 +140,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -172,7 +175,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -309,11 +312,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -393,7 +416,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -600,9 +623,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

qa-only/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -299,11 +302,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -383,7 +406,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -590,9 +613,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

qa/SKILL.md

@@ -54,6 +54,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -133,7 +136,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -168,7 +171,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -305,11 +308,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -389,7 +412,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -596,9 +619,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

retro/SKILL.md

@@ -65,6 +65,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -144,7 +147,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -179,7 +182,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -316,11 +319,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -400,7 +423,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -607,9 +630,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

review/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

scrape/SKILL.md

@@ -46,6 +46,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -125,7 +128,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -160,7 +163,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -297,11 +300,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -381,7 +404,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -588,9 +611,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

scripts/resolvers/composition.ts

@@ -23,7 +23,7 @@ export function generateInvokeSkill(ctx: TemplateContext, args?: string[]): stri
   const DEFAULT_SKIPS = [
     'Preamble (run first)',
     'AskUserQuestion Format',
-    'Completeness Principle — Boil the Lake',
+    'Completeness Principle — Boil the Ocean',
     'Search Before Building',
     'Contributor Mode',
     'Completion Status Protocol',

scripts/resolvers/preamble/generate-ask-user-format.ts

@@ -9,11 +9,31 @@ export function generateAskUserFormat(_ctx: TemplateContext): string {
 
 **Rule:** if any \`mcp__*__AskUserQuestion\` variant is in your tool list, prefer it. Hosts may disable native AUQ via \`--disallowedTools AskUserQuestion\` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report \`BLOCKED — AskUserQuestion unavailable\`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only \`/plan-tune\` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains \`[plan-tune auto-decide] <id> → <option>\` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns \`[Tool result missing due to internal error]\`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on \`SESSION_KIND\` (echoed by the preamble; empty/absent ⇒ \`interactive\`):
+     - \`spawned\` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - \`headless\` → \`BLOCKED — AskUserQuestion unavailable\`; stop and wait (no human can answer).
+     - \`interactive\` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit \`Completeness: X/10\` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a \`Recommendation: <choice> because <reason>\` line plus the \`(recommended)\` marker on that choice.
+
+Layout: a \`D<N>\` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its \`(recommended)\` marker, its \`Completeness: X/10\`, and 2-4 sentences of reasoning — never a bare bullet list; a closing \`Net:\` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 \`\`\`
 D<N> — <one-line question title>
@@ -93,7 +113,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + \`(recommended)\` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \\u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain

scripts/resolvers/preamble/generate-completeness-section.ts

@@ -2,9 +2,9 @@ import type { TemplateContext } from '../types';
 
 export function generateCompletenessSection(ctx?: TemplateContext): string {
   if (ctx?.explainLevel === 'terse') return '';
-  return `## Completeness Principle — Boil the Lake
+  return `## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include \`Completeness: X/10\` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: \`Note: options differ in kind, not coverage — no completeness score.\` Do not fabricate scores.`;
 }

scripts/resolvers/preamble/generate-completion-status.ts

@@ -26,7 +26,7 @@ In plan mode, allowed because they inform the plan: \`$B\`, \`$D\`, \`codex exec
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — \`mcp__*__AskUserQuestion\` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report \`BLOCKED — AskUserQuestion unavailable\` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.`;
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — \`mcp__*__AskUserQuestion\` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: \`headless\` → BLOCKED; \`interactive\` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.`;
 }
 
 export function generateCompletionStatus(ctx: TemplateContext): string {

scripts/resolvers/preamble/generate-lake-intro.ts

@@ -1,7 +1,7 @@
 
 
 export function generateLakeIntro(): string {
-  return `If \`LAKE_INTRO\` is \`no\`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+  return `If \`LAKE_INTRO\` is \`no\`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 \`\`\`bash
 open https://garryslist.org/posts/boil-the-ocean

scripts/resolvers/preamble/generate-preamble-bash.ts

@@ -33,6 +33,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(${ctx.paths.binDir}/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=\${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(${ctx.paths.binDir}/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(${ctx.paths.binDir}/gstack-config get telemetry 2>/dev/null || true)

setup

@@ -1332,6 +1332,7 @@ fi
 # already registered under that tag, the install is a no-op (no prompt).
 PLAN_TUNE_LOG_HOOK="$SOURCE_GSTACK_DIR/hosts/claude/hooks/question-log-hook"
 PLAN_TUNE_PREF_HOOK="$SOURCE_GSTACK_DIR/hosts/claude/hooks/question-preference-hook"
+AUQ_ERROR_FALLBACK_HOOK="$SOURCE_GSTACK_DIR/hosts/claude/hooks/auq-error-fallback-hook"
 PLAN_TUNE_INSTALL_MARKER="$HOME/.gstack/.plan-tune-hooks-prompted"
 
 if [ "$NO_TEAM_MODE" -ne 1 ] \
@@ -1339,9 +1340,13 @@ if [ "$NO_TEAM_MODE" -ne 1 ] \
    && [ -x "$PLAN_TUNE_LOG_HOOK" ] \
    && [ -x "$PLAN_TUNE_PREF_HOOK" ]; then
 
-  # Already installed? Check the settings.json for our source tag.
+  # Already installed? Require BOTH the plan-tune source AND the AUQ-error-fallback
+  # source — so an existing install that predates the fallback hook re-runs the
+  # install (which is idempotent for the plan-tune hooks) and picks up the new one.
   ALREADY_INSTALLED=0
-  if "$SETTINGS_HOOK" list-sources 2>/dev/null | grep -q "plan-tune-cathedral"; then
+  _HOOK_SOURCES=$("$SETTINGS_HOOK" list-sources 2>/dev/null || true)
+  if printf '%s' "$_HOOK_SOURCES" | grep -q "plan-tune-cathedral" \
+     && printf '%s' "$_HOOK_SOURCES" | grep -q "auq-error-fallback"; then
     ALREADY_INSTALLED=1
   fi
 
@@ -1379,6 +1384,21 @@ if [ "$NO_TEAM_MODE" -ne 1 ] \
       --command "$PLAN_TUNE_PREF_HOOK" \
       --source plan-tune-cathedral \
       --timeout 5
+    # AskUserQuestion-failure prose-fallback reliability hook (OV3:B). Fires only when
+    # an AskUserQuestion call returns an error/missing result; inert on success and
+    # inert if the platform doesn't invoke PostToolUse on tool errors. MUST use its
+    # OWN source tag: gstack-settings-hook dedupes by (event, matcher, source) and
+    # REPLACES the entry's hooks, so sharing 'plan-tune-cathedral' would overwrite the
+    # question-log capture hook (same event+matcher). A distinct source = a second
+    # PostToolUse entry; both run in parallel.
+    if [ -x "$AUQ_ERROR_FALLBACK_HOOK" ]; then
+      "$SETTINGS_HOOK" add-event \
+        --event PostToolUse \
+        --matcher '(AskUserQuestion|mcp__.*__AskUserQuestion)' \
+        --command "$AUQ_ERROR_FALLBACK_HOOK" \
+        --source auq-error-fallback \
+        --timeout 5
+    fi
   }
 
   if [ "$ALREADY_INSTALLED" -eq 1 ]; then

setup-browser-cookies/SKILL.md

@@ -42,6 +42,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -121,7 +124,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -156,7 +159,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean

setup-deploy/SKILL.md

@@ -49,6 +49,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -128,7 +131,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -163,7 +166,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -300,11 +303,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -384,7 +407,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -591,9 +614,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

setup-gbrain/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -299,11 +302,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -383,7 +406,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -590,9 +613,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

ship/SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -1202,6 +1225,8 @@ git push -u origin <branch-name>
 
 ---
 
+**PR/MR title invariant (always applies — do not skip even if you don't open the section below):** Any PR or MR you create OR update in the next step MUST have a title that starts with `v$NEW_VERSION` (the version bumped in Step 12), in the format `v<NEW_VERSION> <type>: <summary>`. Never create or edit a PR/MR title without this prefix. Compute the correct title with the single source of truth helper: `~/.claude/skills/gstack/bin/gstack-pr-title-rewrite.sh "$NEW_VERSION" "<current title>"`. The full create/update procedure (idempotency, redaction scan, self-check) is in the section below.
+
 > **STOP.** Before syncing docs and creating or updating the PR/MR (Steps 18-19), Read `~/.claude/skills/gstack/ship/sections/pr-body.md` and execute it
 > in full. Do not work from memory — that section is the source of truth for this step.
 

ship/SKILL.md.tmpl

@@ -395,6 +395,8 @@ git push -u origin <branch-name>
 
 ---
 
+**PR/MR title invariant (always applies — do not skip even if you don't open the section below):** Any PR or MR you create OR update in the next step MUST have a title that starts with `v$NEW_VERSION` (the version bumped in Step 12), in the format `v<NEW_VERSION> <type>: <summary>`. Never create or edit a PR/MR title without this prefix. Compute the correct title with the single source of truth helper: `~/.claude/skills/gstack/bin/gstack-pr-title-rewrite.sh "$NEW_VERSION" "<current title>"`. The full create/update procedure (idempotency, redaction scan, self-check) is in the section below.
+
 {{SECTION:pr-body}}
 
 ## Step 20: Persist ship metrics

ship/sections/pr-body.md

@@ -97,8 +97,8 @@ you missed it.>
 
 ## Linked Spec
 <Auto-detect: look for /spec archives matching this branch via:
-  eval "$(${ctx.paths.binDir}/gstack-paths)"
-  eval "$(${ctx.paths.binDir}/gstack-slug)"
+  eval "$(~/.claude/skills/gstack/bin/gstack-paths)"
+  eval "$(~/.claude/skills/gstack/bin/gstack-slug)"
   CURRENT_BRANCH=$(git branch --show-current)
   SPEC_ARCHIVES="$GSTACK_STATE_ROOT/projects/$SLUG/specs"
   # Find newest archive whose spec_branch frontmatter matches current branch (or one of its

ship/sections/pr-body.md.tmpl

@@ -95,8 +95,8 @@ you missed it.>
 
 ## Linked Spec
 <Auto-detect: look for /spec archives matching this branch via:
-  eval "$(${ctx.paths.binDir}/gstack-paths)"
-  eval "$(${ctx.paths.binDir}/gstack-slug)"
+  eval "$(~/.claude/skills/gstack/bin/gstack-paths)"
+  eval "$(~/.claude/skills/gstack/bin/gstack-slug)"
   CURRENT_BRANCH=$(git branch --show-current)
   SPEC_ARCHIVES="$GSTACK_STATE_ROOT/projects/$SLUG/specs"
   # Find newest archive whose spec_branch frontmatter matches current branch (or one of its

skillify/SKILL.md

@@ -46,6 +46,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -125,7 +128,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -160,7 +163,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -297,11 +300,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -381,7 +404,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -588,9 +611,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

spec/SKILL.md

@@ -47,6 +47,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -126,7 +129,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -161,7 +164,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -298,11 +301,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -382,7 +405,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -589,9 +612,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 
@@ -1045,6 +1068,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -1124,7 +1150,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -1159,7 +1185,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -1296,11 +1322,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -1380,7 +1426,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -1587,9 +1633,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

sync-gbrain/SKILL.md

@@ -48,6 +48,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -127,7 +130,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -162,7 +165,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -299,11 +302,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -383,7 +406,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -590,9 +613,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

test/auq-error-fallback-hook.test.ts

@@ -0,0 +1,131 @@
+/**
+ * auq-error-fallback-hook — the OV3:B runtime reliability layer.
+ *
+ * Two layers of testing:
+ *  - PURE functions (isErrorResponse, directiveFor): deterministic, the core logic.
+ *  - INTEGRATION: spawn the hook as a PostToolUse process with synthetic stdin and
+ *    a controlled env, assert it injects the right directive on an error result and
+ *    stays inert on a real answer.
+ *
+ * NOTE: whether the Claude Code PLATFORM invokes PostToolUse on an MCP
+ * transport/missing-result error is unverified (could not force the Conductor
+ * bug in a harness — see docs/spikes/claude-code-hook-mutation.md). These tests
+ * pin the hook's BEHAVIOR given it is invoked; the platform trigger is the
+ * documented residual risk. The hook is inert if never invoked.
+ */
+import { describe, test, expect } from 'bun:test';
+import { spawnSync } from 'child_process';
+import * as path from 'path';
+import { isErrorResponse, directiveFor } from '../hosts/claude/hooks/auq-error-fallback-hook.ts';
+
+const HOOK = path.resolve(__dirname, '..', 'hosts', 'claude', 'hooks', 'auq-error-fallback-hook.ts');
+
+describe('isErrorResponse — only clear failures, never a real answer', () => {
+  test('null / undefined / empty string are failures', () => {
+    expect(isErrorResponse(null)).toBe(true);
+    expect(isErrorResponse(undefined)).toBe(true);
+    expect(isErrorResponse('')).toBe(true);
+    expect(isErrorResponse('   ')).toBe(true);
+  });
+
+  test('the Conductor missing-result string is a failure', () => {
+    expect(isErrorResponse('[Tool result missing due to internal error]')).toBe(true);
+  });
+
+  test('is_error: true / error-field / sentinel-in-content are failures', () => {
+    expect(isErrorResponse({ is_error: true })).toBe(true);
+    expect(isErrorResponse({ isError: true })).toBe(true);
+    expect(isErrorResponse({ error: 'boom' })).toBe(true);
+    expect(isErrorResponse({ content: 'Tool result missing due to internal error' })).toBe(true);
+  });
+
+  test('a real answer is NOT a failure (no false trigger)', () => {
+    expect(isErrorResponse({ answers: [{ option_label: 'A' }] })).toBe(false);
+    expect(isErrorResponse('A')).toBe(false);
+    // a choice that coincidentally contains "error" must not trip it
+    expect(isErrorResponse({ answers: [{ option_label: 'Fix the error' }] })).toBe(false);
+    expect(isErrorResponse('Investigate the login error')).toBe(false);
+  });
+
+  test('Codex review: narrow detection — generic "error"/"is_error" substrings do NOT trigger', () => {
+    // A real answer mentioning "internal error" must not be read as a failure.
+    expect(isErrorResponse('Investigate the internal error')).toBe(false);
+    // A serialized success payload containing the substring is_error:false must not trigger.
+    expect(isErrorResponse('{"is_error": false, "answer": "A"}')).toBe(false);
+    expect(isErrorResponse({ is_error: false })).toBe(false);
+    expect(isErrorResponse({ content: 'The page had an internal error we fixed' })).toBe(false);
+  });
+});
+
+describe('directiveFor — per-session-kind instruction', () => {
+  test('interactive directive demands the prose triad', () => {
+    const d = directiveFor('interactive');
+    expect(d).toMatch(/ELI10/);
+    expect(d).toMatch(/Completeness: X\/10/);
+    expect(d).toMatch(/\(recommended\)/);
+    expect(d).toMatch(/reply with a letter/i);
+    expect(d).toMatch(/STOP/);
+  });
+
+  test('headless directive BLOCKs', () => {
+    expect(directiveFor('headless')).toMatch(/BLOCKED — AskUserQuestion unavailable/);
+  });
+
+  test('spawned directive auto-chooses', () => {
+    expect(directiveFor('spawned')).toMatch(/auto-choose/i);
+  });
+});
+
+/** Spawn the hook with synthetic stdin + controlled env; parse its JSON stdout. */
+function runHook(stdin: object, env: Record<string, string>): { additionalContext?: string } {
+  const res = spawnSync('bun', [HOOK], {
+    input: JSON.stringify(stdin),
+    encoding: 'utf-8',
+    env: { PATH: process.env.PATH ?? '/usr/bin:/bin', ...env },
+  });
+  const parsed = JSON.parse(res.stdout || '{}');
+  return parsed.hookSpecificOutput ?? {};
+}
+
+describe('hook integration — invoked as PostToolUse', () => {
+  test('error result + headless env → injects BLOCK directive', () => {
+    const out = runHook(
+      { tool_name: 'mcp__conductor__AskUserQuestion', tool_response: '[Tool result missing due to internal error]' },
+      { GSTACK_HEADLESS: '1' },
+    );
+    expect(out.additionalContext).toMatch(/BLOCKED — AskUserQuestion unavailable/);
+  });
+
+  test('error result + interactive env → injects prose-triad directive', () => {
+    const out = runHook(
+      { tool_name: 'AskUserQuestion', tool_response: null },
+      { CONDUCTOR_PORT: '55010' },
+    );
+    expect(out.additionalContext).toMatch(/render the decision as a PROSE message/i);
+    expect(out.additionalContext).toMatch(/Completeness: X\/10/);
+  });
+
+  test('error result + spawned env → injects auto-choose directive', () => {
+    const out = runHook(
+      { tool_name: 'AskUserQuestion', tool_response: { is_error: true } },
+      { OPENCLAW_SESSION: '1' },
+    );
+    expect(out.additionalContext).toMatch(/auto-choose/i);
+  });
+
+  test('SUCCESSFUL answer → no injection (inert on real answers)', () => {
+    const out = runHook(
+      { tool_name: 'AskUserQuestion', tool_response: { answers: [{ option_label: 'A' }] } },
+      { GSTACK_HEADLESS: '1' },
+    );
+    expect(out.additionalContext).toBeUndefined();
+  });
+
+  test('non-AUQ tool → defers (no injection)', () => {
+    const out = runHook(
+      { tool_name: 'Bash', tool_response: null },
+      { GSTACK_HEADLESS: '1' },
+    );
+    expect(out.additionalContext).toBeUndefined();
+  });
+});

test/auq-format-always-loaded.test.ts

@@ -47,6 +47,11 @@ const MANDATORY: Array<{ name: string; re: RegExp }> = [
   { name: 'Completeness coverage rule', re: /Completeness\s*:/i },
   { name: 'kind-vs-coverage rule', re: /options differ in kind/i },
   { name: 'Self-check checklist', re: /Self-check before emitting/i },
+  // The runtime-failure fallback must be ALWAYS-LOADED too: when an AUQ call errors
+  // mid-skill, the model needs the prose-fallback rule in context that instant, not
+  // stranded in an on-demand section. Same guarantee as the format spec above.
+  { name: 'AUQ-failure fallback subsection', re: /When AskUserQuestion is unavailable or a call fails/i },
+  { name: 'fallback SESSION_KIND branch', re: /SESSION_KIND/ },
 ];
 
 /** Per-skill AUQ rules that govern review-finding cadence. A carve may move

test/fixtures/golden/claude-ship-SKILL.md

@@ -50,6 +50,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <(~/.claude/skills/gstack/bin/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$(~/.claude/skills/gstack/bin/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
@@ -129,7 +132,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -164,7 +167,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -301,11 +304,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -385,7 +408,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -592,9 +615,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `~/.claude/skills/gstack/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

test/fixtures/golden/codex-ship-SKILL.md

@@ -36,6 +36,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <($GSTACK_BIN/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$($GSTACK_BIN/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$($GSTACK_BIN/gstack-config get telemetry 2>/dev/null || true)
@@ -115,7 +118,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -150,7 +153,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -287,11 +290,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -371,7 +394,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -578,9 +601,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `$GSTACK_ROOT/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

test/fixtures/golden/factory-ship-SKILL.md

@@ -38,6 +38,9 @@ echo "SKILL_PREFIX: $_SKILL_PREFIX"
 source <($GSTACK_BIN/gstack-repo-mode 2>/dev/null) || true
 REPO_MODE=${REPO_MODE:-unknown}
 echo "REPO_MODE: $REPO_MODE"
+_SESSION_KIND=$($GSTACK_BIN/gstack-session-kind 2>/dev/null || echo "interactive")
+case "$_SESSION_KIND" in spawned|headless|interactive) ;; *) _SESSION_KIND="interactive" ;; esac
+echo "SESSION_KIND: $_SESSION_KIND"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
 _TEL=$($GSTACK_BIN/gstack-config get telemetry 2>/dev/null || true)
@@ -117,7 +120,7 @@ In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`co
 
 ## Skill Invocation During Plan Mode
 
-If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If no variant is callable, the skill is BLOCKED — stop and report `BLOCKED — AskUserQuestion unavailable` per the AskUserQuestion Format rule. At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
+If the user invokes a skill in plan mode, the skill takes precedence over generic plan mode behavior. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; the first AskUserQuestion is the workflow entering plan mode, not a violation of it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" execute. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
 If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
 
@@ -152,7 +155,7 @@ touch ~/.gstack/.writing-style-prompted
 
 Skip if `WRITING_STYLE_PENDING` is `no`.
 
-If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Lake** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
+If `LAKE_INTRO` is `no`: say "gstack follows the **Boil the Ocean** principle — do the complete thing when AI makes marginal cost near-zero. Read more: https://garryslist.org/posts/boil-the-ocean" Offer to open:
 
 ```bash
 open https://garryslist.org/posts/boil-the-ocean
@@ -289,11 +292,31 @@ AI orchestrator (e.g., OpenClaw). In spawned sessions:
 
 **Rule:** if any `mcp__*__AskUserQuestion` variant is in your tool list, prefer it. Hosts may disable native AUQ via `--disallowedTools AskUserQuestion` (Conductor does, by default) and route through their MCP variant; calling native there silently fails. Same questions/options shape; same decision-brief format applies.
 
-**If no AskUserQuestion variant appears in your tool list, this skill is BLOCKED.** Stop, report `BLOCKED — AskUserQuestion unavailable`, and wait for the user. Do not write decisions to the plan file as a substitute, do not emit them as prose and stop, and do not silently auto-decide (only `/plan-tune` AUTO_DECIDE opt-ins authorize auto-picking).
+If AskUserQuestion is unavailable (no variant in your tool list) OR a call to it fails, do NOT silently auto-decide or write the decision to the plan file as a substitute. Follow the **failure fallback** below.
+
+### When AskUserQuestion is unavailable or a call fails
+
+Tell three outcomes apart:
+
+1. **Auto-decide denial (NOT a failure).** The result contains `[plan-tune auto-decide] <id> → <option>` — the preference hook working as designed. Proceed with that option. Do NOT retry, do NOT fall back to prose.
+2. **Genuine failure** — no variant in your tool list, OR the variant is present but the call returns an error / missing result (MCP transport error, empty result, host bug — e.g. Conductor's MCP AskUserQuestion is flaky and returns `[Tool result missing due to internal error]`).
+   - If it was present and **errored** (not absent), retry the SAME call **once** — but only if no answer could have surfaced (a missing-result error can arrive after the user already saw the question; retrying would double-prompt, so if it may have reached them, treat as pending, don't retry).
+   - Then branch on `SESSION_KIND` (echoed by the preamble; empty/absent ⇒ `interactive`):
+     - `spawned` → defer to the **Spawned session** block: auto-choose the recommended option. Never prose, never BLOCKED.
+     - `headless` → `BLOCKED — AskUserQuestion unavailable`; stop and wait (no human can answer).
+     - `interactive` → **prose fallback** (below).
+
+**Prose fallback — render the decision brief as a markdown message, not a tool call.** Same information as the tool format below, different structure (paragraphs, not ✅/❌ bullets). It MUST surface this triad:
+
+1. **A clear ELI10 of the issue itself** — plain English on what's being decided and why it matters (the question, not per-choice), naming the stakes. Lead with it.
+2. **Completeness scores per choice** — explicit `Completeness: X/10` on EACH choice (10 complete, 7 happy-path, 3 shortcut); use the kind-note when options differ in kind not coverage, but never silently drop the score.
+3. **The recommendation and why** — a `Recommendation: <choice> because <reason>` line plus the `(recommended)` marker on that choice.
+
+Layout: a `D<N>` title + a one-line note that AskUserQuestion failed and to reply with a letter; the issue ELI10; the Recommendation line; then ONE paragraph per choice carrying its `(recommended)` marker, its `Completeness: X/10`, and 2-4 sentences of reasoning — never a bare bullet list; a closing `Net:` line. Split chains / 5+ options: one prose block per per-option call, in sequence. Then STOP and wait — the user's typed answer is the decision. In plan mode this satisfies end-of-turn like a tool call.
 
 ### Format
 
-Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose.
+Every AskUserQuestion is a decision brief and must be sent as tool_use, not prose — unless the documented failure fallback above applies (interactive session + the call is unavailable/erroring), in which case the prose fallback is the correct output.
 
 ```
 D<N> — <one-line question title>
@@ -373,7 +396,7 @@ Before calling AskUserQuestion, verify:
 - [ ] (recommended) label on one option (even for neutral-posture)
 - [ ] Dual-scale effort labels on effort-bearing options (human / CC)
 - [ ] Net line closes the decision
-- [ ] You are calling the tool, not writing prose
+- [ ] You are calling the tool, not writing prose — unless the documented failure fallback applies (then: prose with the mandatory triad — issue ELI10, per-choice Completeness, Recommendation + `(recommended)` — and a "reply with a letter" instruction, then STOP)
 - [ ] Non-ASCII characters (CJK / accents) written directly, NOT \u-escaped
 - [ ] If you had 5+ options, you split (or batched into ≤4-groups) — did NOT drop any
 - [ ] If you split, you checked dependencies between options before firing the chain
@@ -580,9 +603,9 @@ Applies to AskUserQuestion, user replies, and findings. AskUserQuestion Format i
 Curated jargon list lives at `$GSTACK_ROOT/scripts/jargon-list.json` (80+ terms). On the first jargon term you encounter this session, Read that file once; treat the `terms` array as the canonical list. The list is repo-owned and may grow between releases.
 
 
-## Completeness Principle — Boil the Lake
+## Completeness Principle — Boil the Ocean
 
-AI makes completeness cheap. Recommend complete lakes (tests, edge cases, error paths); flag oceans (rewrites, multi-quarter migrations).
+AI makes completeness cheap, so the complete thing is the goal. Recommend full coverage (tests, edge cases, error paths) — boil the ocean one lake at a time. The only thing out of scope is genuinely unrelated work (rewrites, multi-quarter migrations); flag that as separate scope, never as an excuse for a shortcut.
 
 When options differ in coverage, include `Completeness: X/10` (10 = all edge cases, 7 = happy path, 3 = shortcut). When options differ in kind, write: `Note: options differ in kind, not coverage — no completeness score.` Do not fabricate scores.
 

test/gen-skill-docs.test.ts

@@ -1,4 +1,4 @@
-import { describe, test, expect } from 'bun:test';
+import { describe, test, expect, beforeAll } from 'bun:test';
 import { COMMAND_DESCRIPTIONS } from '../browse/src/commands';
 import { SNAPSHOT_FLAGS } from '../browse/src/snapshot';
 import * as fs from 'fs';
@@ -2125,6 +2125,21 @@ describe('Factory generation (--host factory)', () => {
 import { ALL_HOST_CONFIGS, getExternalHosts } from '../hosts/index';
 
 describe('Parameterized host smoke tests', () => {
+  // Regenerate every external host up front so the per-host `--dry-run` freshness
+  // checks are deterministic. These host dirs (.agents/.factory/.cursor/...) are
+  // gitignored regenerated artifacts, so the freshness check is really an
+  // idempotency/determinism check — it still catches non-deterministic gen, but no
+  // longer flakes on stale-on-disk state left by a missing `gen --host all` prestep
+  // (the canonical `bun test` does not run one). The tracked-claude freshness test
+  // (`generated files are fresh`) runs earlier and is unaffected.
+  beforeAll(() => {
+    for (const h of getExternalHosts()) {
+      Bun.spawnSync(['bun', 'run', 'scripts/gen-skill-docs.ts', '--host', h.name], {
+        cwd: ROOT, stdout: 'pipe', stderr: 'pipe',
+      });
+    }
+  });
+
   for (const hostConfig of getExternalHosts()) {
     describe(`${hostConfig.displayName} (--host ${hostConfig.name})`, () => {
       const hostDir = path.join(ROOT, hostConfig.hostSubdir, 'skills');
@@ -2208,6 +2223,16 @@ describe('Parameterized host smoke tests', () => {
 // ─── --host all tests ────────────────────────────────────────
 
 describe('--host all', () => {
+  // Same determinism guard as the parameterized block: make external hosts fresh on
+  // disk so `--host all --dry-run` reports FRESH regardless of prior state.
+  beforeAll(() => {
+    for (const h of getExternalHosts()) {
+      Bun.spawnSync(['bun', 'run', 'scripts/gen-skill-docs.ts', '--host', h.name], {
+        cwd: ROOT, stdout: 'pipe', stderr: 'pipe',
+      });
+    }
+  });
+
   test('--host all generates for all registered hosts', () => {
     const result = Bun.spawnSync(['bun', 'run', 'scripts/gen-skill-docs.ts', '--host', 'all', '--dry-run'], {
       cwd: ROOT, stdout: 'pipe', stderr: 'pipe',

test/gstack-session-kind.test.ts

@@ -0,0 +1,70 @@
+/**
+ * gstack-session-kind — classifies the session so skills know whether a human can
+ * answer an AskUserQuestion. Drives the AUQ-failure fallback branch:
+ *   spawned     → auto-choose (orchestrator)
+ *   headless    → BLOCK on AUQ failure
+ *   interactive → prose fallback on AUQ failure
+ *
+ * These permutations are the contract the resolver rule depends on. Run with a
+ * SCRUBBED env (the test process itself runs inside Conductor, so CONDUCTOR_* /
+ * CLAUDE_CODE_* would leak in and contaminate the classification).
+ *
+ * Free, deterministic, gate-tier.
+ */
+import { describe, test, expect } from 'bun:test';
+import { execFileSync } from 'child_process';
+import * as path from 'path';
+
+const BIN = path.resolve(__dirname, '..', 'bin', 'gstack-session-kind');
+
+/** Run the helper with ONLY the supplied env (plus PATH so bash resolves). */
+function kind(env: Record<string, string>): string {
+  return execFileSync(BIN, [], {
+    env: { PATH: process.env.PATH ?? '/usr/bin:/bin', ...env },
+    encoding: 'utf-8',
+  }).trim();
+}
+
+describe('gstack-session-kind', () => {
+  test('OPENCLAW_SESSION → spawned (highest precedence)', () => {
+    expect(kind({ OPENCLAW_SESSION: '1' })).toBe('spawned');
+    // spawned wins even when other markers are also present
+    expect(kind({ OPENCLAW_SESSION: '1', GSTACK_HEADLESS: '1', CONDUCTOR_PORT: '5' })).toBe('spawned');
+  });
+
+  test('GSTACK_HEADLESS → headless', () => {
+    expect(kind({ GSTACK_HEADLESS: '1' })).toBe('headless');
+  });
+
+  test('CONDUCTOR_* → interactive (a human host is present)', () => {
+    expect(kind({ CONDUCTOR_WORKSPACE_PATH: '/tmp/ws' })).toBe('interactive');
+    expect(kind({ CONDUCTOR_PORT: '55010' })).toBe('interactive');
+  });
+
+  test('CLAUDE_CODE_ENTRYPOINT=cli → interactive', () => {
+    expect(kind({ CLAUDE_CODE_ENTRYPOINT: 'cli' })).toBe('interactive');
+  });
+
+  test('interactive host beats CI markers', () => {
+    expect(kind({ CONDUCTOR_PORT: '5', CI: '1' })).toBe('interactive');
+  });
+
+  test('CI / GITHUB_ACTIONS with no host → headless', () => {
+    expect(kind({ CI: '1' })).toBe('headless');
+    expect(kind({ GITHUB_ACTIONS: 'true' })).toBe('headless');
+  });
+
+  test('GSTACK_HEADLESS beats CONDUCTOR (explicit override wins)', () => {
+    expect(kind({ GSTACK_HEADLESS: '1', CONDUCTOR_PORT: '5' })).toBe('headless');
+  });
+
+  test('bare env → interactive (degrade-safe default)', () => {
+    expect(kind({})).toBe('interactive');
+  });
+
+  test('empty GSTACK_HEADLESS is treated as unset (interactive)', () => {
+    // The resolver/helper guard on -n, so an empty string must NOT mean headless —
+    // this is the opt-out path harness suites use to exercise the interactive branch.
+    expect(kind({ GSTACK_HEADLESS: '' })).toBe('interactive');
+  });
+});

test/helpers/agent-sdk-runner.ts

@@ -300,6 +300,13 @@ export async function runAgentSdkTest(
   const queryImpl: QueryProvider = opts.queryProvider ?? query;
   const model = opts.model ?? 'claude-opus-4-7';
 
+  // NOTE on GSTACK_HEADLESS: the SDK child inherits process.env, so headless
+  // classification for eval/E2E runs is set by the `test:gate` / `test:evals`
+  // package.json scripts (scoped to that invocation), NOT mutated here. We must not
+  // pass sdkOpts.env (it breaks the SDK auth pipeline — see CLAUDE.md) and must not
+  // mutate process.env ambiently (it would leak headless into later interactive-path
+  // tests in the same Bun process — Codex review finding).
+
   let attempt = 0;
   let lastErr: unknown = null;
 

test/helpers/carve-guards.ts

@@ -87,6 +87,12 @@ export interface CarveGuard {
   minUnionBytes: number;
   /** Parity: content phrases the union must preserve. */
   mustContain: string[];
+  /**
+   * Parity: optional per-skill override for the union size-growth ceiling vs the
+   * v1.53.0.0 baseline (default 1.05). Bumped only when a deliberate cross-cutting
+   * preamble feature legitimately grows a smaller carved skeleton past 5%.
+   */
+  maxSizeRatio?: number;
 }
 
 export const CARVE_GUARDS: Record<string, CarveGuard> = {
@@ -106,8 +112,14 @@ export const CARVE_GUARDS: Record<string, CarveGuard> = {
     scenario:
       'This is a FRESH version-changing ship: the branch has a real code change, VERSION still equals the base version (needs a bump), and CHANGELOG.md needs a new entry. Follow the skill flow for a version-changing ship: run the pre-landing review and prepare the CHANGELOG entry. Produce the ship plan / review report. Do NOT actually commit, push, or open a PR.',
     staticInvariants: {
-      mustStayInSkeleton: [],
-      mustMoveToSection: [],
+      // The PR-title-version invariant MUST stay always-loaded: the v1.54.0.0
+      // carve stranded it in pr-body.md and PRs started landing with bare titles
+      // (CI backstop: test/pr-title-sync-workflow-safety.test.ts).
+      mustStayInSkeleton: ['v$NEW_VERSION', 'gstack-pr-title-rewrite'],
+      // ...while the full create/update procedure stays carved into pr-body.md
+      // (out of the skeleton, present in the union). Asserts BOTH PR paths
+      // survive: the create path and the idempotent update path.
+      mustMoveToSection: ['gh pr create --base', 'gh pr edit --title'],
       // ship is operational (multi-STOP, not a plan review); no single post-STOP gate.
       gateAfterStop: undefined,
     },
@@ -216,6 +228,11 @@ export const CARVE_GUARDS: Record<string, CarveGuard> = {
     maxSkeletonBytes: 50_000,
     minUnionBytes: 55_000,
     mustContain: ['CHANGELOG', 'Diataxis', 'coverage'],
+    // The AUQ-failure prose fallback (v1.57.2.0) adds ~2KB to every skill's
+    // always-loaded preamble; on this small carved skeleton that lands at ~5.9%
+    // over the pre-carve/pre-AUQ v1.53.0.0 baseline. Headroom for the
+    // cross-cutting addition; all other skills keep the strict 1.05 ceiling.
+    maxSizeRatio: 1.08,
   },
   'design-consultation': {
     skill: 'design-consultation',

test/helpers/parity-harness.ts

@@ -252,7 +252,7 @@ const CARVED_INVARIANTS: ParityInvariant[] = Object.values(CARVE_GUARDS).map((g)
   minBytes: g.minUnionBytes,
   mustContain: g.mustContain,
   mustHaveHeadings: ['## Preamble', '## When to invoke'],
-  maxSizeRatio: 1.05,
+  maxSizeRatio: g.maxSizeRatio ?? 1.05,
 }));
 
 export const PARITY_INVARIANTS: ParityInvariant[] = [

test/helpers/providers/claude.ts

@@ -52,6 +52,9 @@ export class ClaudeAdapter implements ProviderAdapter {
         timeout: opts.timeoutMs,
         encoding: 'utf-8',
         maxBuffer: 32 * 1024 * 1024,
+        // Default GSTACK_HEADLESS=1 so a benchmark run classifies as headless (an
+        // AskUserQuestion failure BLOCKs rather than emitting unanswerable prose).
+        env: { ...process.env, GSTACK_HEADLESS: '1' },
       });
       const parsed = this.parseOutput(out);
       return {

test/helpers/session-runner.ts

@@ -176,7 +176,11 @@ export async function runSkillTest(options: {
 
   const proc = Bun.spawn(['sh', '-c', `cat "${promptFile}" | claude ${args.map(a => `"${a}"`).join(' ')}`], {
     cwd: workingDirectory,
-    env: extraEnv ? { ...process.env, ...extraEnv } : undefined,
+    // Default GSTACK_HEADLESS=1 so eval/E2E runs classify as headless (BLOCK on an
+    // AskUserQuestion failure rather than emit a prose question no human reads). A
+    // suite exercising the INTERACTIVE prose-fallback path opts out by passing
+    // `env: { GSTACK_HEADLESS: '' }` — extraEnv wins because it spreads last.
+    env: { ...process.env, GSTACK_HEADLESS: '1', ...extraEnv },
     stdout: 'pipe',
     stderr: 'pipe',
   });

test/pr-title-sync-workflow-safety.test.ts

@@ -0,0 +1,135 @@
+/**
+ * pr-title-sync.yml is a `pull_request_target` workflow — static injection
+ * tripwire (gate, free).
+ *
+ * The anxiety this kills: `pull_request_target` runs with a WRITE token in the
+ * base-repo context, even for fork PRs. That is what lets this workflow rewrite
+ * fork-PR titles (the backstop). It is also the single most dangerous workflow
+ * trigger in GitHub Actions. Two classic footguns turn it into remote code
+ * execution / token theft, and `actionlint` catches NEITHER:
+ *
+ *   1. Checking out the PR head (`actions/checkout` with a `ref:` pointing at
+ *      `pull_request.head` / `head_ref`) and then running anything from it —
+ *      that executes attacker-controlled fork code with the write token.
+ *   2. Interpolating an attacker-controlled `${{ github.event.pull_request.* }}`
+ *      field directly INSIDE a `run:` block — the title/body are attacker-
+ *      controlled and the `${{ }}` is expanded into the shell before execution,
+ *      so a crafted title runs as code. Those fields MUST arrive via `env:` and
+ *      be referenced as `"$VAR"` (shell-quoted), never inlined.
+ *
+ * This tripwire reads the workflow file directly and fails CI if either pattern
+ * reappears. Mirrors the static-grep invariant tests in browse/test
+ * (terminal-agent-pid-identity, server-sanitize-surrogates).
+ *
+ * Note: `gh api ... -q '.head.sha'` inside a run block is SAFE (reading PR
+ * metadata as data via a jq filter string, not `${{ }}` interpolation), so we
+ * ban the interpolation form specifically, not the literal substring `head.sha`.
+ */
+import { describe, test, expect } from 'bun:test';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+
+const WORKFLOW = path.resolve(__dirname, '..', '.github', 'workflows', 'pr-title-sync.yml');
+
+/** Indentation width (count of leading spaces) of a line. */
+function indent(line: string): number {
+  const m = line.match(/^( *)/);
+  return m ? m[1].length : 0;
+}
+
+/**
+ * Return the lines that live inside a `run:` block, each tagged with its 1-based
+ * line number. Handles both `run: |` (multiline) and `run: <inline command>`.
+ */
+function runBlockLines(content: string): Array<{ n: number; text: string }> {
+  const lines = content.split('\n');
+  const out: Array<{ n: number; text: string }> = [];
+  let inRun = false;
+  let runIndent = -1;
+  for (let i = 0; i < lines.length; i++) {
+    const line = lines[i];
+    const n = i + 1;
+    const inlineRun = line.match(/^(\s*)run:\s*(\S.*)$/); // `run: echo foo`
+    const blockRun = /^(\s*)run:\s*(\|>?[+-]?)?\s*$/.test(line); // `run: |`
+    if (inlineRun && !/^\|/.test(inlineRun[2])) {
+      out.push({ n, text: inlineRun[2] });
+      inRun = false;
+      continue;
+    }
+    if (blockRun) {
+      inRun = true;
+      runIndent = indent(line);
+      continue;
+    }
+    if (inRun) {
+      if (line.trim() === '') {
+        out.push({ n, text: line });
+        continue;
+      }
+      // Block ends when a non-empty line is indented at or below the `run:` key.
+      if (indent(line) <= runIndent) {
+        inRun = false;
+      } else {
+        out.push({ n, text: line });
+      }
+    }
+  }
+  return out;
+}
+
+describe('pr-title-sync.yml pull_request_target safety', () => {
+  const content = fs.readFileSync(WORKFLOW, 'utf-8');
+
+  test('workflow file exists', () => {
+    expect(fs.existsSync(WORKFLOW)).toBe(true);
+  });
+
+  test('does NOT check out the PR head ref (no fork-code execution)', () => {
+    const offenders: string[] = [];
+    content.split('\n').forEach((line, i) => {
+      // A checkout `ref:` (or any `ref:`) pointing at the PR head is the footgun.
+      if (/ref:\s*\$\{\{[^}]*(pull_request\.head|head_ref)/.test(line)) {
+        offenders.push(`  L${i + 1}: ${line.trim()}`);
+      }
+    });
+    if (offenders.length > 0) {
+      throw new Error(
+        `pr-title-sync.yml checks out the PR head under pull_request_target — that ` +
+          `runs attacker-controlled fork code with a write token. Check out the base ` +
+          `repo (no ref:) and read PR-head data via the API instead.\n` +
+          offenders.join('\n'),
+      );
+    }
+  });
+
+  test('does NOT interpolate ${{ github.event.pull_request.* }} inside a run: block', () => {
+    const offenders: string[] = [];
+    for (const { n, text } of runBlockLines(content)) {
+      if (/\$\{\{\s*github\.event\.pull_request/.test(text)) {
+        offenders.push(`  L${n}: ${text.trim()}`);
+      }
+    }
+    if (offenders.length > 0) {
+      throw new Error(
+        `pr-title-sync.yml inlines an attacker-controlled PR field into a run: block ` +
+          `— a crafted PR title/body executes as shell. Pass it via env: and ` +
+          `reference "$VAR" (shell-quoted) instead.\n` +
+          offenders.join('\n'),
+      );
+    }
+  });
+
+  test('uses pull_request_target (the hardening is actually present)', () => {
+    // Positive assertion: if someone reverts to plain pull_request, the fork
+    // backstop silently stops working (read-only token). Keep it intentional.
+    expect(/^on:\s*$/m.test(content) || /\bpull_request_target\b/.test(content)).toBe(true);
+    expect(content).toMatch(/\bpull_request_target\b/);
+  });
+
+  test('passes the PR title through env:, not raw interpolation', () => {
+    // The safe pattern: OLD_TITLE: ${{ github.event.pull_request.title }} in an
+    // env: mapping, consumed as "$OLD_TITLE" in script.
+    expect(content).toMatch(/env:/);
+    expect(content).toMatch(/github\.event\.pull_request\.title/);
+  });
+});

test/resolver-ask-user-format.test.ts

@@ -16,6 +16,8 @@
  * for the weekly periodic eval to notice.
  */
 import { describe, test, expect } from 'bun:test';
+import * as fs from 'fs';
+import * as path from 'path';
 import type { TemplateContext } from '../scripts/resolvers/types';
 import { HOST_PATHS } from '../scripts/resolvers/types';
 import { generateAskUserFormat } from '../scripts/resolvers/preamble/generate-ask-user-format';
@@ -161,3 +163,88 @@ describe('generateAskUserFormat — 5+ option split rule (slim inline + docs poi
     expect(out).toContain('**Non-ASCII characters');
   });
 });
+
+describe('generateAskUserFormat — runtime-failure prose fallback', () => {
+  const out = generateAskUserFormat(makeCtx());
+
+  test('documents the unavailable/failed subsection', () => {
+    expect(out).toMatch(/When AskUserQuestion is unavailable or a call fails/i);
+  });
+
+  test('carves out the auto-decide denial as NOT a failure', () => {
+    expect(out).toContain('[plan-tune auto-decide]');
+    expect(out).toMatch(/NOT a failure/i);
+    // and explicitly: do not fall back to prose on an auto-decide denial
+    expect(out).toMatch(/Do NOT[\s\S]{0,40}fall back to prose|never prose/i);
+  });
+
+  test('retries the errored call exactly once before degrading', () => {
+    expect(out).toMatch(/retry the SAME call \*\*once\*\*|retry the same call.*once/i);
+    // idempotency guard against double-prompting
+    expect(out).toMatch(/double-prompt|no answer could have surfaced/i);
+  });
+
+  test('branches on SESSION_KIND: spawned / headless / interactive', () => {
+    expect(out).toContain('SESSION_KIND');
+    expect(out).toMatch(/`spawned`[\s\S]*auto-choose/);
+    expect(out).toMatch(/`headless`[\s\S]*BLOCKED/);
+    expect(out).toMatch(/`interactive`[\s\S]*prose fallback/);
+    // empty/absent SESSION_KIND degrades to interactive
+    expect(out).toMatch(/empty\/absent[\s\S]{0,40}interactive/i);
+  });
+
+  // The mandatory triad the user explicitly required for the plain-text output.
+  test('prose fallback mandates the triad: issue ELI10', () => {
+    expect(out).toMatch(/ELI10 of the issue itself/i);
+  });
+
+  test('prose fallback mandates the triad: per-choice Completeness score', () => {
+    expect(out).toMatch(/Completeness scores per choice/i);
+    expect(out).toMatch(/Completeness: X\/10.*EACH choice|on EACH choice/i);
+  });
+
+  test('prose fallback mandates the triad: recommendation + (recommended) marker', () => {
+    expect(out).toMatch(/Recommendation: <choice> because/);
+    expect(out).toMatch(/\(recommended\)`? marker on that choice/);
+  });
+
+  test('prose fallback is one paragraph per choice, not a bare bullet list', () => {
+    expect(out).toMatch(/ONE paragraph per choice/i);
+    expect(out).toMatch(/never a bare bullet list/i);
+  });
+
+  test('prose fallback tells the user to reply with a letter, then STOP', () => {
+    expect(out).toMatch(/reply with a letter/i);
+    expect(out).toMatch(/STOP and wait/i);
+  });
+
+  // OV2: the former "tool_use, not prose" assertions must carry the qualifier so the
+  // fallback is not self-contradicting. Guards against the instruction collision
+  // silently returning on a future edit.
+  test('OV2: the Format line qualifies "not prose" with the fallback exception', () => {
+    expect(out).toMatch(/must be sent as tool_use, not prose — unless the documented failure fallback/);
+  });
+
+  test('OV2: the self-check "not writing prose" line carries the fallback qualifier', () => {
+    expect(out).toMatch(/not writing prose — unless the documented failure fallback applies/);
+  });
+});
+
+describe('CQ2 — cross-file invariant: auto-decide prefix matches the hook', () => {
+  const out = generateAskUserFormat(makeCtx());
+  const hookSrc = fs.readFileSync(
+    path.resolve(__dirname, '..', 'hosts', 'claude', 'hooks', 'question-preference-hook.ts'),
+    'utf-8',
+  );
+
+  test('the hook actually emits the [plan-tune auto-decide] prefix', () => {
+    expect(hookSrc).toContain('[plan-tune auto-decide]');
+  });
+
+  test('the resolver references the exact same prefix the hook emits', () => {
+    // If a future edit reworded the hook reason, this catches the drift: the prose
+    // fallback would stop recognizing the auto-decide denial as not-a-failure.
+    const PREFIX = '[plan-tune auto-decide]';
+    expect(hookSrc.includes(PREFIX) && out.includes(PREFIX)).toBe(true);
+  });
+});

test/skill-validation.test.ts

@@ -837,7 +837,7 @@ describe('Completeness Principle in generated SKILL.md files', () => {
     test(`${skill} contains Completeness Principle section`, () => {
       const content = fs.readFileSync(path.join(ROOT, skill), 'utf-8');
       expect(content).toContain('Completeness Principle');
-      expect(content).toContain('Boil the Lake');
+      expect(content).toContain('Boil the Ocean');
     });
   }
 

test/terse-build.test.ts

@@ -64,10 +64,10 @@ describe('terse build — per-resolver behavior', () => {
   });
 
   describe('generateCompletenessSection', () => {
-    test('default: emits full section with Boil-the-Lake prose', () => {
+    test('default: emits full section with Boil-the-Ocean prose', () => {
       const out = generateCompletenessSection(makeCtx('default'));
       expect(out).toContain('## Completeness Principle');
-      expect(out).toContain('Boil the Lake');
+      expect(out).toContain('Boil the Ocean');
     });
 
     test('terse: returns empty string', () => {