diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 2b2ef364..5311c2cd 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -192,7 +192,25 @@ gen-skill-docs.ts      (reads source code metadata)
 SKILL.md               (committed, auto-generated sections)
 ```
 
-Templates contain the workflows, tips, and examples that require human judgment. The `{{COMMAND_REFERENCE}}` and `{{SNAPSHOT_FLAGS}}` placeholders are filled from `commands.ts` and `snapshot.ts` at build time. This is structurally sound — if a command exists in code, it appears in docs. If it doesn't exist, it can't appear.
+Templates contain the workflows, tips, and examples that require human judgment. Placeholders are filled from source code at build time:
+
+| Placeholder | Source | What it generates |
+|-------------|--------|-------------------|
+| `{{COMMAND_REFERENCE}}` | `commands.ts` | Categorized command table |
+| `{{SNAPSHOT_FLAGS}}` | `snapshot.ts` | Flag reference with examples |
+| `{{PREAMBLE}}` | `gen-skill-docs.ts` | Startup block: update check, session tracking, contributor mode, AskUserQuestion format |
+| `{{BROWSE_SETUP}}` | `gen-skill-docs.ts` | Binary discovery + setup instructions |
+
+This is structurally sound — if a command exists in code, it appears in docs. If it doesn't exist, it can't appear.
+
+### The preamble
+
+Every skill starts with a `{{PREAMBLE}}` block that runs before the skill's own logic. It handles four things in a single bash command:
+
+1. **Update check** — calls `gstack-update-check`, reports if an upgrade is available.
+2. **Session tracking** — touches `~/.gstack/sessions/$PPID` and counts active sessions (files modified in the last 2 hours). When 3+ sessions are running, all skills enter "ELI16 mode" — every question re-grounds the user on context because they're juggling windows.
+3. **Contributor mode** — reads `gstack_contributor` from config. When true, the agent files casual field reports to `~/.gstack/contributor-logs/` when gstack itself misbehaves.
+4. **AskUserQuestion format** — universal format: context, question, `RECOMMENDATION: Choose X because ___`, lettered options. Consistent across all skills.
 
 ### Why committed, not generated at runtime?
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ae6b4fb..44980dcc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,20 @@
 # Changelog
 
+## 0.4.1 — 2026-03-16
+
+### For users
+
+- **Contributor mode.** Run `gstack-config set gstack_contributor true` and gstack starts filing field reports when it hits its own bugs. You'll see a casual "hey gstack team, this didn't work" note appear in `~/.gstack/contributor-logs/` — open your fork and fix it.
+- **Session awareness.** If you're running 3+ gstack sessions at once, every question now re-grounds you: project, branch, what you're working on, what it's asking. No more "wait, which window is this?"
+- **Consistent recommendations.** Every question gstack asks you now ends with a clear `RECOMMENDATION: Choose X because ___` before the options. Same format everywhere.
+- **Enum completeness checks in /review.** New critical review category that traces new enum values, status strings, and type constants through every consumer outside the diff. Catches the "added a value but forgot to handle it in the switch statement" class of bugs.
+
+### For contributors
+
+- Renamed `{{UPDATE_CHECK}}` placeholder to `{{PREAMBLE}}` across all skill templates — single startup block now handles update check, session tracking, contributor mode, and question formatting.
+- DRY'd plan-ceo-review and plan-eng-review question formatting to reference the preamble baseline.
+- Added vendored symlink awareness docs to CLAUDE.md.
+
 ## 0.4.0 — 2026-03-16
 
 ### Added
diff --git a/VERSION b/VERSION
index 1d0ba9ea..267577d4 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.4.0
+0.4.1
diff --git a/qa-only/SKILL.md b/qa-only/SKILL.md
index 8d6f2b11..438b7826 100644
--- a/qa-only/SKILL.md
+++ b/qa-only/SKILL.md
@@ -15,15 +15,63 @@ allowed-tools:
 <!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
 <!-- Regenerate: bun run gen:skill-docs -->
 
-## Update Check (run first)
+## Preamble (run first)
 
 ```bash
 _UPD=$(~/.claude/skills/gstack/bin/gstack-update-check 2>/dev/null || .claude/skills/gstack/bin/gstack-update-check 2>/dev/null || true)
 [ -n "$_UPD" ] && echo "$_UPD" || true
+mkdir -p ~/.gstack/sessions
+touch ~/.gstack/sessions/"$PPID"
+_SESSIONS=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
+find ~/.gstack/sessions -mmin +120 -type f -delete 2>/dev/null || true
+_CONTRIB=$(~/.claude/skills/gstack/bin/gstack-config get gstack_contributor 2>/dev/null || true)
 ```
 
 If output shows `UPGRADE_AVAILABLE <old> <new>`: read `~/.claude/skills/gstack/gstack-upgrade/SKILL.md` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If `JUST_UPGRADED <from> <to>`: tell user "Running gstack v{to} (just updated!)" and continue.
 
+## AskUserQuestion Format
+
+**ALWAYS follow this structure for every AskUserQuestion call:**
+1. Context: project name, current branch, what we're working on (1-2 sentences)
+2. The specific question or decision point
+3. `RECOMMENDATION: Choose [X] because [one-line reason]`
+4. Lettered options: `A) ... B) ... C) ...`
+
+If `_SESSIONS` is 3 or more: the user is juggling multiple gstack sessions and context-switching heavily. **ELI16 mode** — they may not remember what this conversation is about. Every AskUserQuestion MUST re-ground them: state the project, the branch, the current plan/task, then the specific problem, THEN the recommendation and options. Be extra clear and self-contained — assume they haven't looked at this window in 20 minutes.
+
+Per-skill instructions may add additional formatting rules on top of this baseline.
+
+## Contributor Mode
+
+If `_CONTRIB` is `true`: you are in **contributor mode**. When you hit friction with **gstack itself** (not the user's app), file a field report. Think: "hey, I was trying to do X with gstack and it didn't work / was confusing / was annoying. Here's what happened."
+
+**gstack issues:** browse command fails/wrong output, snapshot missing elements, skill instructions unclear or misleading, binary crash/hang, unhelpful error message, any rough edge or annoyance — even minor stuff.
+**NOT gstack issues:** user's app bugs, network errors to user's URL, auth failures on user's site.
+
+**To file:** write `~/.gstack/contributor-logs/{slug}.md` with this structure:
+
+```
+# {Title}
+
+Hey gstack team — ran into this while using /{skill-name}:
+
+**What I was trying to do:** {what the user/agent was attempting}
+**What happened instead:** {what actually happened}
+**How annoying (1-5):** {1=meh, 3=friction, 5=blocker}
+
+## Steps to reproduce
+1. {step}
+
+## Raw output
+(wrap any error messages or unexpected output in a markdown code block)
+
+**Date:** {YYYY-MM-DD} | **Version:** {gstack version} | **Skill:** /{skill}
+```
+
+Then run: `mkdir -p ~/.gstack/contributor-logs && open ~/.gstack/contributor-logs/{slug}.md`
+
+Slug: lowercase, hyphens, max 60 chars (e.g. `browse-snapshot-ref-gap`). Skip if file already exists. Max 3 reports per session. File inline and continue — don't stop the workflow. Tell user: "Filed gstack field report: {title}"
+
 # /qa-only: Report-Only QA Testing
 
 You are a QA engineer. Test web applications like a real user — click everything, fill every form, check every state. Produce a structured report with evidence. **NEVER fix anything.**
diff --git a/qa-only/SKILL.md.tmpl b/qa-only/SKILL.md.tmpl
index 7ad936bb..5d49e201 100644
--- a/qa-only/SKILL.md.tmpl
+++ b/qa-only/SKILL.md.tmpl
@@ -13,7 +13,7 @@ allowed-tools:
   - AskUserQuestion
 ---
 
-{{UPDATE_CHECK}}
+{{PREAMBLE}}
 
 # /qa-only: Report-Only QA Testing