gstack/CONTRIBUTING.md

Contributing to gstack

Thanks for wanting to make gstack better. Whether you're fixing a typo in a skill prompt or building an entirely new workflow, this guide will get you up and running fast.

Quick start

gstack skills are Markdown files that Claude Code discovers from a skills/ directory. Normally they live at ~/.claude/skills/gstack/ (your global install). But when you're developing gstack itself, you want Claude Code to use the skills in your working tree — so edits take effect instantly without copying or deploying anything.

That's what dev mode does. It symlinks your repo into the local .claude/skills/ directory so Claude Code reads skills straight from your checkout.

git clone https://github.com/garrytan/gstack.git && cd gstack
bun install                    # install dependencies
bin/dev-setup                  # activate dev mode

Full clone vs shallow. The README's user-facing install uses --depth 1 for speed. As a contributor, use a full clone (no --depth flag) — you'll need history for git log, git blame, git bisect, and reviewing PRs against earlier versions. If you already have a --depth 1 clone from following the README, promote it to a full clone with git fetch --unshallow.

Now edit any SKILL.md, invoke it in Claude Code (e.g. /review), and see your changes live. When you're done developing:

bin/dev-teardown               # deactivate — back to your global install

Operational self-improvement

gstack automatically learns from failures. At the end of every skill session, the agent reflects on what went wrong (CLI errors, wrong approaches, project quirks) and logs operational learnings to ~/.gstack/projects/{slug}/learnings.jsonl. Future sessions surface these learnings automatically, so gstack gets smarter on your codebase over time.

No setup needed. Learnings are logged automatically. View them with /learn.

The contributor workflow

1. Use gstack normally — operational learnings are captured automatically
2. Check your learnings: /learn or ls ~/.gstack/projects/*/learnings.jsonl
3. Fork and clone gstack (if you haven't already)
4. Symlink your fork into the project where you hit the bug:

   # In your core project (the one where gstack annoyed you)
   ln -sfn /path/to/your/gstack-fork .claude/skills/gstack
   cd .claude/skills/gstack && bun install && bun run build && ./setup
   

   Setup creates per-skill directories with SKILL.md symlinks inside (qa/SKILL.md -> gstack/qa/SKILL.md), links each skill's runtime assets alongside (sections/, templates, checklists — everything except SKILL.md, tests, build output, and .tmpl sources), and asks your prefix preference. Pass --no-prefix to skip the prompt and use short names.
5. Fix the issue — your changes are live immediately in this project
6. Test by actually using gstack — do the thing that annoyed you, verify it's fixed
7. Open a PR from your fork

This is the best way to contribute: fix gstack while doing your real work, in the project where you actually felt the pain.

Session awareness

When you have 3+ gstack sessions open simultaneously, every question tells you which project, which branch, and what's happening. No more staring at a question thinking "wait, which window is this?" The format is consistent across all skills.

Working on gstack inside the gstack repo

When you're editing gstack skills and want to test them by actually using gstack in the same repo, bin/dev-setup wires this up. It creates .claude/skills/ symlinks (gitignored) pointing back to your working tree, so Claude Code uses your local edits instead of the global install.

gstack/                          <- your working tree
├── .claude/skills/              <- created by dev-setup (gitignored)
│   ├── gstack -> ../../         <- symlink back to repo root
│   ├── review/                  <- real directory (short name, default)
│   │   └── SKILL.md -> gstack/review/SKILL.md
│   ├── ship/                    <- or gstack-review/, gstack-ship/ if --prefix
│   │   └── SKILL.md -> gstack/ship/SKILL.md
│   └── ...                      <- one directory per skill
├── review/
│   └── SKILL.md                 <- edit this, test with /review
├── ship/
│   └── SKILL.md
├── browse/                      <- /browse skill + gstack's own browser engine (the fallback)
│   ├── src/                     <- TypeScript source
│   └── dist/                    <- compiled binary (gitignored)
├── lib/
│   ├── aside-render.ts          <- local-HTML rendering: Aside first, browse engine fallback
│   └── design-catalog.ts        <- typed design anti-pattern catalog; review/design-checklist.md is generated from it
├── bin/
│   └── gstack-render.ts         <- the CLI skills call to render a local HTML file
└── ...

Setup creates real directories (not symlinks) at the top level with a SKILL.md symlink inside, plus links to each skill's runtime assets (sections/, templates, checklists). Alias skills (_gstack-command, connect-chrome) install as rewritten copies, never symlinks — editing a symlinked alias would corrupt the generated source. This ensures Claude discovers them as top-level skills, not nested under gstack/. Names depend on your prefix setting (~/.gstack/config.yaml). Short names (/review, /ship) are the default. Run ./setup --prefix if you prefer namespaced names (/gstack-review, /gstack-ship).

Day-to-day workflow

# 1. Enter dev mode
bin/dev-setup

# 2. Edit a skill template (SKILL.md files are generated — edit the .tmpl)
vim review/SKILL.md.tmpl
bun run gen:skill-docs   # or: bun run dev:skill (watch mode, auto-regen on change)

# 3. Test it in Claude Code — changes are live
#    > /review

# 4. Editing browse source? Rebuild the binary
bun run build

# 5. Done for the day? Tear down
bin/dev-teardown

Brain-aware blocks in a dev workspace (gbrain installed)

If gbrain is installed and usable (bin/gstack-gbrain-detect --is-ok exits 0), bin/dev-setup keeps your tracked SKILL.md files canonical and renders the brain-aware variant (the GBRAIN_CONTEXT_LOAD / GBRAIN_SAVE_RESULTS blocks) into .claude/gstack-rendered/ (gitignored, per-workspace). It then repoints the workspace's SKILL.md symlinks at that render, so your Claude sessions get the full gbrain experience while git status stays clean. Under the hood, dev-setup passes GSTACK_SKIP_GBRAIN_REGEN=1 inline to the nested ./setup (so it never dirties tracked source) and runs gen:skill-docs:user --out-dir .claude/gstack-rendered, which rewrites only the section-base paths to point at the render. bin/dev-teardown removes the render. To make the blocks live across your other projects' Claude sessions, run gstack-config gbrain-refresh, which renders them to a user render dir (${GSTACK_USER_RENDER_DIR:-~/.gstack/render/claude}, swapped in only on a successful render) and repoints the installed skills at it via gstack-relink — the global install checkout stays git-clean, and the refresh is guarded so it never touches a symlinked or non-gstack directory.

Testing & evals

Codex evals and the GPT benchmark adapter default to gpt-6-astra: explicit model > GSTACK_CODEX_MODEL > default. Claude capture and judge defaults are claude-fable-5-1, resolved through lib/eval-model.ts:

• Claude session, PTY, and Agent SDK eval runners and the Claude benchmark adapter: explicit model > EVALS_MODEL > GSTACK_EVAL_MODEL_CAPTURE > GSTACK_EVAL_MODEL > default.
• Shared judge calls (including benchmark quality scoring): explicit model > GSTACK_EVAL_MODEL_JUDGE > GSTACK_EVAL_MODEL > default. EVALS_MODEL applies to capture runners, not judges.

Warmup stays on claude-haiku-4-5; distill stays on claude-haiku-4-5-20251001. Explicit test and historical benchmark model selections still win. Known frontier defaults are maintained in releases; there is no automatic model discovery. Paid-run costs shown below are historical estimates from before this default change, not measurements of the new defaults.

Setup

Development and tests require Bun 1.4.0 or newer; CI pins and tests 1.4.0. Earlier Linux versions can close unrelated live file descriptors during subprocess garbage collection, causing intermittent browser and HTTP fixture failures (upstream diagnosis).

# 1. Copy .env.example and add your API key
cp .env.example .env
# Edit .env → set ANTHROPIC_API_KEY=sk-ant-...

# 2. Install deps (if you haven't already)
bun install

Bun auto-loads .env — no extra config. Conductor workspaces inherit .env from the main worktree automatically (see "Conductor workspaces" below).

Test tiers

Tier	Command	Cost	What it tests
1 — Static	bun run test	Free	Command validation, snapshot flags, Aside contract pins, render-wrapper option mapping, SKILL.md correctness, TODOS-format.md refs, observability unit tests
2 — E2E	bun run test:e2e	~$4.20	Full skill execution via claude -p subprocess
3 — LLM eval	EVALS=1 bun test test/skill-llm-eval.test.ts	~$0.15 standalone	LLM-as-judge scoring of generated SKILL.md docs
2+3	bun run test:evals	~$4 combined	E2E + LLM-as-judge (runs both)

bun run test:quick           # Measured fast free subset for ordinary edits; not full acceptance
bun run eval:bg:pr           # Changed fast live probes + selected quality judges, detached
bun run test                 # Final full free acceptance after focused repairs and source freeze
bun run test:e2e             # Tier 2: E2E only (needs EVALS=1, can't run inside Claude Code)
bun run test:evals           # Tier 2 + 3 combined (~$4.35/run)

The PR paid gate uses an explicit short behavioral profile. Every selected quality judge remains included; the manifest lists deferred behaviors separately from passes. Unknown source dependencies restore the full gate. A new prompt without registered coverage fails planning. Known broad behaviors remain visibly deferred when their prompts change; they do not silently gain PR-pass credit. The full gate and periodic censuses run fresh weekly and on manual dispatch of evals-periodic.yml; bun run eval:bg:release runs both locally. Some broad behavioral failures will therefore be found after the PR gate.

CI enables verified first-attempt reuse for the 14 workflow quality judges for 24 hours within the same PR. The other 11 quality cases and all dynamic agent cases stay fresh. Local runs stay fresh unless the complete scoped cache and runtime configuration is supplied. The key includes complete prompt bytes, generated inputs, fixtures, runner/rubric code, installed dependencies, model settings and runtime. The current assertions validate a reused score again. Records retain the original run, revision and time; reuse never renews that time. Failed, retried, partial or unknown-input results cannot be reused. EVALS_FRESH=1 bypasses reuse; periodic and release runs always bypass it.

Timing goals are under one minute for edit feedback, 3–5 minutes for typical PR checks, and 60–90 seconds for complete free test execution across isolated CI machines. They are targets, not timeout reductions or guarantees. The complete local suite keeps six workers and currently takes roughly 4–5 minutes; use test:quick for the shorter edit loop. CI setup, build and queue time are reported separately. Refresh measurements with bun run test:free --record-durations; the required free CI lane packs the complete inventory across isolated runners, then checks every shard's receipt before reporting success. Local worker counts remain bounded to avoid browser/process contention.

Measurements from this PR on 2026-09-21:

Run	Coverage	Elapsed
Local edit feedback	861 of 993 free test files	38 seconds
Local complete free suite	All 993 files, six workers	4m 35s
Complete Linux CI	All 993 files, 20 isolated runners	1m 40s across test steps; 3m 7s including setup and aggregation

The Linux CI run on 25030d68 included one recorded successful retry. Its slowest test step was 77 seconds; staggered starts made the complete test span longer. Typical PR paid-gate timing still needs measurement on a small change; test-runner changes use the full fallback.

Follow Validation discipline in AGENTS.md: reproduce known failures with focused checks, verify adjacent source and generation contracts, then run the affected and remaining required selected evaluations. Finish review fixes and release preparation before running the full free suite once on the frozen code. During repairs, focused checks replace a full-suite run before every commit.

Tier 1: Static validation (free)

Runs with bun run test, which routes through scripts/test-free-shards.ts: N concurrent shard processes under a strict output contract — a shard that exits without bun's own terminal summary line, or a crashed worker, fails the run, so silent truncation can never report green. Pass --verbose to forward the full child stream; --wall-timeout <secs> overrides the per-shard kill deadline. GSTACK_FREE_JOBS=<n> overrides the shard count (digits only, loud on garbage), and GSTACK_FREE_RETRY_FLAKY=1 opts into one serial retry pass for syscall-supervised sandboxes (off by default locally — dev boxes should see flakes; the required CI free lane turns it on and uploads every flaky pass in a JSONL ledger artifact that bun run eval:flake-rank folds in). Working in a cloud sandbox? Run scripts/sandbox-doctor.sh once per boot to make the suite run green (details in docs/TESTING_INTERNALS.md). Don't type bare bun test for the suite: it walks the whole repo, loads paid eval files, and misses the strict classifier. No API keys needed.

• Skill parser tests (test/skill-parser.test.ts) — Extracts every $B command from SKILL.md bash code blocks and validates against the command registry in browse/src/commands.ts. Catches typos, removed commands, and invalid snapshot flags.
• Skill validation tests (test/skill-validation.test.ts) — Validates that SKILL.md files reference only real commands and flags, and that command descriptions meet quality thresholds. Also cross-checks the skill inventory in AGENTS.md and docs/skills.md.
• Aside driver contract (test/aside-driver.test.ts) — Browser behaviour in skills is written against scripts/resolvers/aside.ts ({{ASIDE_SETUP}}) and verified live against the Aside CLI on a Mac. CI cannot run Aside, so the Aside E2E tests self-skip where aside is not installed; the static pins (detection, fallback hand-off, consent, credential, one-flow-per-script, sentinel) are what CI proves.
• Aside render wrapper (test/aside-render.test.ts) — Pins the option mapping and generated script of lib/aside-render.ts everywhere, and drives both engines hermetically with fake aside / browse executables (probe classification, the stdout contract, loopback-server policy, failure paths, the timeout kill, engine choice and the mid-run fallback); the live render (PDF + screenshot through a real Aside) runs only where Aside is open and self-skips elsewhere. make-pdf's render gates (make-pdf/test/e2e/*-gate.test.ts) and test/skill-e2e-diagram.test.ts are engine-agnostic: they run through whichever engine resolves (browserAvailable() — Aside, or the browse binary bun run build:gates compiles, which is what Linux CI does) and skip only when neither exists.
• Render CLI (test/gstack-render-cli.test.ts) — Pins bin/gstack-render.ts against a fake daemon (GSTACK_SKIP_ASIDE=1 + GSTACK_BROWSE_BIN): argv guards exit 1 with the usage line, --help exits 0, ENGINE= first then OK <path> then fenced EVAL / PAGE_ERRORS, --serve-root containment, the no-browser first line, and prompt exit after a successful render. make-pdf/test/cli-exit-codes.test.ts and make-pdf/test/setup-smoke.test.ts pin the pdf binary's error-to-exit-code map and $P setup's engine report.
• Generator tests (test/gen-skill-docs.test.ts) — Tests the template system: verifies placeholders resolve correctly, output includes value hints for flags (e.g. -d <N> not just -d), enriched descriptions for key commands (e.g. is lists valid states, press lists key examples).
• Design detector, catalog, and DESIGN.md (test/gstack-design-detect.test.ts, test/design-detect-contract.test.ts, test/design-catalog.test.ts, test/design-checklist-sync.test.ts, test/design-md.test.ts, test/frontend-scope.test.ts, test/impeccable-fixtures.test.ts) — Drive bin/gstack-design-detect.ts through the fake engine in test/fixtures/fake-impeccable.ts (probe order, the never-execute-a-repository-file rule, the --changed target allow-list, design_detector: off, analytics lines, output sanitizing), pin the catalog invariants and the generated review/design-checklist.md, round-trip the open DESIGN.md reader/writer, and check the real engine captures (test/fixtures/impeccable-*.json, engine 0.1.3) against the contract. test/dom-dump-hygiene.test.ts runs lib/dom-dump.js in a real Chromium page through the built browse binary; it self-skips without the binary and is opt-in outside CI (GSTACK_DOM_DUMP_HYGIENE=1).
• Tier-alignment invariant (test/e2e-tier-alignment.test.ts) — For every self-gated test/skill-e2e-*.test.ts named in a touchfiles dep list, the file's EVALS_TIER self-gate must match its declared tier in E2E_TIERS. Kills the "inert demotion" class where a test is re-tiered in touchfiles.ts but the file still gates on the old tier and keeps running in the wrong lane. Unmapped or mixed-tier files are reported, never silently skipped.
• Catalog budget (test/catalog-budget.test.ts) — Caps the aggregate discovery surface: the sum of every skill's frontmatter name + description (what every host loads at discovery, every session) must stay under 1,150 token-equivalents, with a 260-byte per-skill cap. Counting goes through the shared census in test/helpers/skill-census.ts (physical files vs authored skills vs registry entries — three deliberately different counts). Adding a skill? The failure message carries the re-measure + ratchet protocol.
• Context-budget ratchet (test/context-budget-ratchet.test.ts) — CI ceilings on the two token ledgers the catalog budget doesn't cover: the always-on full-frontmatter aggregate and each skill's per-invocation eager tokens (SKILL.md + forced-read references), graded against test/fixtures/context-budget.json via lib/context-bill.ts. New skills fail until they have a ceiling; ceilings for removed skills must be pruned. Legitimate growth or a landed reduction: re-run bun test/helpers/capture-context-budget.ts and commit the refreshed fixture in the same commit, so the change is a visible decision in the diff.
• Dependency security regressions (test/dependency-security.test.ts) — Run bun test test/dependency-security.test.ts to check the resolved sharp and adm-zip version floors, load Sharp, verify ordinary ZIP extraction, and reject extraction through destination-file and destination-directory symlinks. The symlink cases skip Windows. These checks complement the OSV scan; they do not change its existing exceptions.

Tier 2: E2E via claude -p (~$4.20/run)

Spawns claude -p as a subprocess with --output-format stream-json --verbose, streams NDJSON for real-time progress, and scans for browse errors. This is the closest thing to "does this skill actually work end-to-end?"

# Must run from a plain terminal — can't nest inside Claude Code or Conductor
EVALS=1 bun test test/skill-e2e-*.test.ts

• Gated by EVALS=1 env var (prevents accidental expensive runs)
• Auto-skips if running inside Claude Code (claude -p can't nest)
• API connectivity pre-check — fails fast on ConnectionRefused before burning budget
• Real-time progress to stderr: [Ns] turn T tool #C: Name(...)
• Saves full NDJSON transcripts and failure JSON for debugging
• Tests live in test/skill-e2e-*.test.ts (split by category), runner logic in test/helpers/session-runner.ts

Hermetic by default. Every E2E runner (claude -p, the real-PTY plan-mode runner, the Agent SDK runner, plus the codex and gemini runners) spawns its child through test/helpers/hermetic-env.ts: an allowlist-scrubbed environment, a fresh seeded CLAUDE_CONFIG_DIR, a temp GSTACK_HOME, and --strict-mcp-config. Your operator ~/.claude config, MCP servers (gbrain, Conductor), skills, ~/.gstack decision logs, and CONDUCTOR_* env never leak into the child, so local eval signal matches CI instead of disagreeing for reasons unrelated to the code under test. The hermetic CLAUDE_CONFIG_DIR seeds no skills by default; a PTY test that types a /skill slash command passes seedSkills: true to the PTY runner, which swaps in hermeticSkillsConfigDir() — a seeded skill registry that symlinks the LIVE working tree's SKILL.md files (by design: the skills are the subject under test, so a snapshot would measure stale copies). Set EVALS_HERMETIC=0 to debug against your real operator state (this also drops --strict-mcp-config). The wiring is pinned by test/hermetic-wiring.test.ts (a free static tripwire), two gate-tier isolation canaries in test/skill-e2e-hermetic-canary.test.ts, and the skill-seeding tripwires in test/hermetic-skills-seeding.test.ts / test/pty-skill-seeding-wiring.test.ts.

E2E observability

When E2E tests run, they produce machine-readable artifacts in ~/.gstack-dev/:

Artifact	Path	Purpose
Heartbeat	e2e-live.json	Current test status (updated per tool call)
Partial results	evals/_partial-e2e.json	Completed tests (survives kills)
Progress log	e2e-runs/{runId}/progress.log	Append-only text log
NDJSON transcripts	e2e-runs/{runId}/{test}.ndjson	Raw claude -p output per test
Failure JSON	e2e-runs/{runId}/{test}-failure.json	Diagnostic data on failure

Live dashboard: Run bun run eval:watch in a second terminal to see a live dashboard showing completed tests, the currently running test, and cost. Use --tail to also show the last 10 lines of progress.log.

Eval history tools:

bun run eval:list            # list all eval runs (turns, duration, cost per run)
bun run eval:compare         # compare two runs — shows per-test deltas + Takeaway commentary
bun run eval:summary         # aggregate stats + per-test efficiency averages across runs
bun run eval:flake-rank      # rank tests by flake signal: retried passes first, then failure rate (--json, --dir, --since-days)

Detached runs for agents and long suites. When an agent (or you, for a run you don't want to babysit) launches a long eval, use the eval:bg* scripts. They wrap the eval command in bin/gstack-detach: a fresh session that escapes a turn-boundary SIGTERM, a caffeinate wrapper that blocks idle-sleep, a machine-wide gstack-evals lock so concurrent worktrees serialize instead of saturating the model API, a run-scoped log under ~/.gstack-dev/eval-runs/, a per-tier watchdog, and a guaranteed ### gstack-detach EXIT=<code> ### sentinel so a poller never mistakes silence for success.

bun run eval:bg              # detached test:evals (diff-based)
bun run eval:bg:all          # detached test:evals:all
bun run eval:bg:gate         # detached gate-tier suite
bun run eval:bg:periodic     # detached periodic-tier suite

Each prints its log path. The gate and periodic variants run their tier through the sharded paid runner (scripts/test-paid-shards.ts, also available directly as bun run test:gate:sharded / bun run test:periodic:sharded): one Bun process per test file, an external wall-clock timeout that kills the shard's whole process group (stray claude/codex grandchildren included), a per-shard eval dir (GSTACK_EVAL_DIR=<evalDir>/shards/<slug>/), and an aggregate that distinguishes failed vs timed-out vs never-started shards. The runner also selects by diff: shards untouched by your branch are reported as skipped-by-diff, with a selection banner naming the reason (EVALS_ALL=1 forces everything). EVALS_JOBS sets how many shard processes run at once (default 8); EVALS_CONCURRENCY is bun's concurrency WITHIN a shard (default 2) — they are deliberately separate knobs. eval:list, eval:compare, eval:summary, and eval:flake-rank are shard-aware. Humans running bun run test:evals foreground in their own terminal don't need this — Ctrl-C is intended there.

Eval comparison commentary: eval:compare generates natural-language Takeaway sections interpreting what changed between runs — flagging regressions, noting improvements, calling out efficiency gains (fewer turns, faster, cheaper), and producing an overall summary. This is driven by generateCommentary() in eval-store.ts.

Artifacts are never cleaned up — they accumulate in ~/.gstack-dev/ for post-mortem debugging and trend analysis.

Tier 3: LLM-as-judge (~$0.15/run)

Uses claude-fable-5-1 by default to score generated SKILL.md docs on three dimensions. Override the judge model per run with GSTACK_EVAL_MODEL_JUDGE:

• Clarity — Can an AI agent understand the instructions without ambiguity?
• Completeness — Are all commands, flags, and usage patterns documented?
• Actionability — Can the agent execute tasks using only the information in the doc?

Each dimension is scored 1-5. Threshold: every dimension must score ≥ 4. There's also a regression test that compares generated docs against the hand-maintained baseline from origin/main — generated must score equal or higher.

# Needs ANTHROPIC_API_KEY in .env — included in bun run test:evals

• Resolves the judge model through lib/eval-model.ts, using the override order above
• Tests live in test/skill-llm-eval.test.ts
• Calls the Anthropic API directly (not claude -p), so it works from anywhere including inside Claude Code

CI

A GitHub Action (.github/workflows/skill-docs.yml) generates all hosts on pushes to main and on PRs, then rejects tracked differences and nonignored untracked output. Generation errors also fail the job. Optional ignored host caches are not compared against Git.

Supply-chain gates run alongside it:

• Quality gate (.github/workflows/quality-gate.yml, every PR and push) — scans the diff's added lines for credentials using gstack's own redact engine (.github/scripts/gate-secret-scan.mjs). HIGH findings fail the job; MEDIUM findings surface as an advisory count. Fails closed if the scan can't produce a report. Also gates critical dependency advisories and runs ShellCheck on the setup/build boundaries.
• Dependency review (.github/workflows/dependency-review.yml) — reviews dependency changes on PRs that touch lockfiles or workflow files.
• OSV scanner (.github/workflows/osv-scanner.yml) — weekly vulnerability scan against the OSV database. Config lives in .osv-scanner.toml and is loaded via an explicit --config flag (OSV does not auto-discover that filename); every ignore entry needs a reason and an ignoreUntil expiry, enforced by test/osv-config-wiring.test.ts.
• Dependabot (.github/dependabot.yml) — grouped dependency update PRs.

The supply-chain workflows pin their third-party actions to commit SHAs. The PR template (.github/PULL_REQUEST_TEMPLATE.md) asks for evidence — tests run, eval output — not promises.

Tests run against the browse binary directly — they don't require dev mode. Anything that needs Aside itself (test/skill-e2e-aside.test.ts, the Aside qa/design cases, the live render in test/aside-render.test.ts) runs only on a Mac with the Aside app open and self-skips elsewhere; make-pdf's render gates and the /diagram E2E run on whichever engine resolves, so CI runs them on the browse binary it builds with bun run build:gates.

Editing SKILL.md files

SKILL.md files are generated from .tmpl templates. Don't edit the .md directly — your changes will be overwritten on the next build.

# 1. Edit the template
vim SKILL.md.tmpl              # or browse/SKILL.md.tmpl

# 2. Regenerate for all hosts
bun run gen:skill-docs --host all

# 3. Check health (reports all hosts)
bun run skill:check

# Or use watch mode — auto-regenerates on save
bun run dev:skill

skill:check renders all hosts into temporary storage using canonical content paths and host defaults, validates the complete generated content, and compares expected tracked artifacts against the checkout. Missing, changed, or nonignored untracked output fails. Local ignored host caches, including symlinked caches, are left untouched; the checker works without them. A generation failure cannot produce a successful check of partial output.

For template authoring best practices (natural language over bash-isms, dynamic branch detection, {{BASE_BRANCH_DETECT}} usage), see CLAUDE.md's "Writing SKILL templates" section.

Browser steps in skills are aside repl scripts that follow the cookbook in scripts/resolvers/aside.ts, each paired with its $B equivalent for the fallback engine; run the Aside shape against the Aside CLI before committing. To add a browse command, add it to browse/src/commands.ts. To add a snapshot flag, add it to SNAPSHOT_FLAGS in browse/src/snapshot.ts. Then rebuild.

Render through lib/aside-render.ts; don't bundle puppeteer/Chromium in a skill. A skill that needs to rasterize or print its own HTML/JSON (diagrams, cards, og-images, PDFs) calls bin/gstack-render.ts from its template (--screenshot, --pdf, --eval JS --out FILE) or imports render from lib/aside-render.ts in TypeScript (renderWithAside / renderWithBrowse are the engine-specific halves; render picks between them and retries once on the browse engine if Aside's CLI cannot start or loses its CDP bridge mid-run). The wrapper prints through Aside when it is open and through the browse daemon when it is not (newtab --json, goto the loopback URL, js readiness polling, pdf --from-file, viewport + screenshot, js --out, closetab) — the one shared Chromium per box, same flags and OK <path> lines, ENGINE=aside|browse saying which one actually rendered, EVAL / PAGE_ERRORS lines fenced as untrusted web content. The loopback server serves one per-render secret URL and never follows a symlink out of its directory. Sized screenshots are 1x on the fallback (2x on Aside); JPEG quality and pageRanges/scale are Aside-only; --landscape swaps paper dimensions. Never npm i puppeteer, never download a second Chromium that drifts out of version sync, never point the renderer at a website. If the wrapper lacks an option you need, add it to lib/aside-render.ts (pin it in test/aside-render.test.ts, and in test/gstack-render-cli.test.ts when it is a CLI flag) so every caller gets it on both paths. Exported test seams: pickEngine(fresh, deps) (inject the probe and the binary resolver), serveDir(root, nonce), SAFE_TMP_DIR, and PAGE_NUMBER_FOOTER (the one page-number footer make-pdf, gstack-render, and the browse pdf command share).

Jargon list (V1 writing style)

gstack's Writing Style section (injected into every tier-≥2 skill's preamble) glosses technical terms on first use per skill invocation. The list of terms that qualify for glossing lives at scripts/jargon-list.json — ~50 curated high-frequency terms (idempotent, race condition, N+1, backpressure, etc.). Terms not on the list are assumed plain-English enough.

Adding or removing a term: open a PR editing scripts/jargon-list.json. Run bun run gen:skill-docs after the edit — terms are baked into every generated SKILL.md at gen time, so changes take effect only after regeneration. No runtime loading; no user-side override. The repo list is the source of truth.

Good candidates for addition: high-frequency terms that non-technical users encounter in review output without context (common database/concurrency terminology, security jargon, frontend framework concepts). Don't add terms that only appear in one or two niche skills — the cost-to-value trade isn't worth the review overhead.

Multi-host development

gstack generates SKILL.md files for 10 hosts from one set of .tmpl templates. Each host is a typed config in hosts/*.ts. The generator reads these configs to produce host-appropriate output (different frontmatter, paths, tool names).

Supported hosts: Claude (primary), Codex, Factory, Kiro, OpenCode, Slate, Cursor, OpenClaw, Hermes, GBrain.

Generating for all hosts

# Generate for a specific host
bun run gen:skill-docs                    # Claude (default)
bun run gen:skill-docs --host codex       # Codex
bun run gen:skill-docs --host opencode    # OpenCode
bun run gen:skill-docs --host all         # All 10 hosts

# Or use build, which does all hosts + compiles binaries
bun run build

What changes between hosts

Each host config (hosts/*.ts) controls:

Aspect	Example (Claude vs Codex)
Output directory	{skill}/SKILL.md vs .agents/skills/gstack-{skill}/SKILL.md
Frontmatter	Full (name, description, hooks, version) vs minimal (name + description)
Paths	~/.claude/skills/gstack vs $GSTACK_ROOT
Tool names	"use the Bash tool" vs same (Factory rewrites to "run this command")
Hook skills	hooks: frontmatter vs inline safety advisory prose
Suppressed sections	GBrain blocks vs GBrain blocks and Review Army; Codex retains outside-review sections routed to Claude Code
Model overlay	claude vs gpt (per-host defaultModel; --model or, at setup time, the Codex config.toml model overrides)

See scripts/host-config.ts for the full HostConfig interface.

Testing host output

# Run all static tests (includes parameterized smoke tests for all hosts)
bun run test

# Check freshness for all hosts
bun run gen:skill-docs --host all --dry-run

# Health dashboard covers all hosts
bun run skill:check

Adding a new host

See docs/ADDING_A_HOST.md for the full guide. Short version:

1. Create hosts/myhost.ts (copy from hosts/opencode.ts)
2. Add to hosts/index.ts
3. Add .myhost/ to .gitignore
4. Run bun run gen:skill-docs --host myhost
5. Run bun run test (parameterized tests auto-cover it)

Zero generator, setup, or tooling code changes needed.

Adding a new skill

When you add a new skill template, all hosts get it automatically:

1. Create {skill}/SKILL.md.tmpl
2. Run bun run gen:skill-docs --host all
3. The dynamic template discovery picks it up, no static list to update
4. Budget it: run bun test/helpers/capture-context-budget.ts and commit the refreshed test/fixtures/context-budget.json — the context-budget ratchet fails any skill without a ceiling
5. Commit {skill}/SKILL.md, external host output is generated at setup time and gitignored

Conductor workspaces

If you're using Conductor to run multiple Claude Code sessions in parallel, conductor.json wires up workspace lifecycle automatically:

Hook	Script	What it does
setup	bin/dev-setup	Copies .env from main worktree, installs deps, symlinks skills, runs ./setup non-interactively, and (if gbrain is installed) renders brain-aware blocks into .claude/gstack-rendered/ without dirtying tracked source
archive	bin/dev-teardown	Removes skill symlinks, the .claude/gstack-rendered/ render, and cleans up .claude/ directory

When Conductor creates a new workspace, bin/dev-setup runs automatically. It detects the main worktree (via git worktree list), copies your .env so API keys carry over, and sets up dev mode — no manual steps needed.

bin/dev-setup runs ./setup fully non-interactively (it passes --plan-tune-hooks=prompt and closes stdin), so a forwarded Conductor TTY can never hang on a hidden setup prompt. It also never installs the plan-tune Claude Code hooks, which means a throwaway workspace can't rewrite your global ~/.claude/settings.json to point at an ephemeral worktree path. To install the plan-tune hooks deliberately, run ./setup --plan-tune-hooks outside dev-setup (or gstack-config set plan_tune_hooks yes). The explicit flag counts as an explicit decision: setup's Conductor auto-opt-in for AskUserQuestion hooks fires only on the true silent fall-through (no flag, no GSTACK_PLAN_TUNE_HOOKS env var, no plan_tune_hooks key literally present in config, checked via gstack-config has), so it can never override dev-setup into installing hooks. One stated repair exception: setup's heal-first pass (gstack-settings-hook prune-stale --repoint) may prune dead gstack hook entries and re-point existing ones at the stable ~/.claude/skills/gstack install. That is strictly convergent repair, never a new registration, and registration itself is canonical-only, so an ephemeral tree path can never be baked into settings.json.

First-time setup: Put your ANTHROPIC_API_KEY in .env in the main repo (see .env.example). Every Conductor workspace inherits it automatically.

GSTACK_* env prefix (Conductor-injected keys). Conductor explicitly strips ANTHROPIC_API_KEY and OPENAI_API_KEY from every workspace's process env. The .env copy path doesn't restore them either — the strip happens after env inheritance. Users who want paid evals, /sync-gbrain embeddings, or claude-agent-sdk calls to work in a Conductor workspace must set GSTACK_ANTHROPIC_API_KEY and GSTACK_OPENAI_API_KEY in Conductor's workspace env config; Conductor passes those through untouched. On the gstack side, TS entry points import lib/conductor-env-shim.ts as a side effect, which promotes GSTACK_FOO_API_KEY to FOO_API_KEY when the canonical name is empty. If you add a new TS entry point that hits a paid API, add import "../lib/conductor-env-shim"; to the top of the file. Today the shim is imported from bin/gstack-gbrain-sync.ts, bin/gstack-model-benchmark, scripts/preflight-agent-sdk.ts, and test/helpers/e2e-helpers.ts.

Things to know

• SKILL.md files are generated. Edit the .tmpl template, not the .md. Run bun run gen:skill-docs to regenerate. The same run generates review/design-checklist.md from lib/design-catalog.ts and lib/dom-dump.js from lib/dom-dump-script.ts: edit those sources, never the generated files (test/design-checklist-sync.test.ts fails on drift).
• TODOS.md is the unified backlog. Organized by skill/component with P0-P4 priorities. /ship auto-detects completed items. All planning/review/retro skills read it for context.
• Browse, make-pdf, design, and lib/ source changes need a rebuild. If you touch browse/src/*.ts, make-pdf/src/*.ts, design/src/*.ts, or anything under lib/ (the canonical claude-bin.ts, error-handling.ts, and aside-render.ts the binaries embed, plus design-catalog.ts, whose MOCKUP_NEVER_NAMES the design binary's mockup prompt embeds; browse/src re-exports the first three), run bun run build. ./setup makes the same call on its own: it rebuilds when any of the three binaries is missing or when those sources, package.json, or bun.lock are newer than the browse binary (test/setup-needs-build.test.ts pins the decision).
• Dev mode shadows your global install. Project-local skills take priority over ~/.claude/skills/gstack. bin/dev-teardown restores the global one.
• Conductor workspaces are independent. Each workspace is its own git worktree. bin/dev-setup runs automatically via conductor.json.
• .env propagates across worktrees. Set it once in the main repo, all Conductor workspaces get it.
• .claude/skills/ is gitignored. The symlinks never get committed.
• Never write raw ln -snf in setup. Every link site in setup MUST route through the _link_or_copy SRC DST helper near the IS_WINDOWS detection. The helper preserves ln -snf on Unix and switches to cp -R / cp -f on Windows without Developer Mode, where plain ln -snf produces frozen file copies that don't refresh on git pull. test/setup-windows-fallback.test.ts enforces this with a static invariant — a single raw ln call outside the helper body fails CI.
• Synchronous subagent dispatches must state the flag. Claude Code runs Agent-tool subagents in the background by default (since v2.1.198), so any template step that dispatches a subagent and consumes its output must carry run_in_background: false. Use the {{FOREGROUND_DISPATCH_NOTE}} placeholder (scripts/resolvers/constants.ts) instead of hand-writing the guidance, and add the generated carrier file to GENERATED_WITH_GUIDANCE in test/run-in-background-guidance.test.ts in the same commit — its structural scanner fails CI on any generated dispatch imperative that lacks the flag.
• Never delete or link over a skill entry setup cannot prove is gstack's. Every destructive site in setup (the linker, the alias installer, both prefix-flip cleanups) and in bin/gstack-relink goes through the ownership helpers (_claude_entry_is_ours / _claude_entry_owned_strongly in setup, _entry_is_ours / _entry_owned_strongly in relink). The retired-skill prune (_prune_stale_generated) applies the same strong/weak split through its own gate: a real host directory is a candidate only when its SKILL.md carries the generated banner (_owned_for_windows_refresh), a host symlink is removed only when it resolves into gstack (_gstack_target_is_ours), a bannered real directory is cleaned through _cleanup_weak_dir, and a symlink inside the render tree is never followed. A symlink into gstack or the .gstack-owned marker proves the whole directory; a byte-identical or generated-banner SKILL.md proves only that file, and a differing one is moved to ~/.gstack/backups/skills/<ts>/ first. test/setup-link-ownership.test.ts, test/setup-cleanup-orphans.test.ts, test/setup-prune-stale-generated.test.ts, and test/relink.test.ts pin it. The rule is duplicated in the two scripts until the shared helper filed in TODOS.md lands: change both.
• ./setup never fails on Chromium. The Playwright bootstrap (section # 2 of setup) is best-effort and bounded: every failure becomes a reason code (skipped, chromium-install, chromium-install-timeout, chromium-install-locked, windows-no-node, windows-node-modules, post-install-launch) printed in the final summary alongside the browser-dependent skills, and skill registration always runs. GSTACK_PLAYWRIGHT_INSTALL_TIMEOUT=<seconds> (default 600) bounds the download; GSTACK_SKIP_PLAYWRIGHT=1 skips it, the right knob for a no-browser box or a setup-only test loop. GSTACK_SKIP_ASIDE=1 makes the browser summary (like the skills' probe and the renderer) treat Aside as absent, so the summary never promises a fallback the bootstrap did not deliver (test/setup-browser-hint.test.ts). Anything you add after the bootstrap must stay independent of the browser. test/setup-playwright-best-effort.test.ts pins the block.

Testing your changes in a real project

This is the recommended way to develop gstack. Symlink your gstack checkout into the project where you actually use it, so your changes are live while you do real work.

Step 1: Symlink your checkout

# In your core project (not the gstack repo)
ln -sfn /path/to/your/gstack-checkout .claude/skills/gstack

Step 2: Run setup to create per-skill symlinks

The gstack symlink alone isn't enough. Claude Code discovers skills through individual top-level directories (qa/SKILL.md, ship/SKILL.md, etc.), not through the gstack/ directory itself. Run ./setup to create them:

cd .claude/skills/gstack && bun install && bun run build && ./setup

Setup will ask whether you want short names (/qa) or namespaced (/gstack-qa). Your choice is saved to ~/.gstack/config.yaml and remembered for future runs. To skip the prompt, pass --no-prefix (short names) or --prefix (namespaced).

Step 3: Develop

Edit a template, run bun run gen:skill-docs, and the next /review or /qa call picks it up immediately. No restart needed.

Going back to the stable global install

Remove the project-local symlink. Claude Code falls back to ~/.claude/skills/gstack/:

rm .claude/skills/gstack

The per-skill directories (qa/, ship/, etc.) contain SKILL.md symlinks that point to gstack/..., so they'll resolve to the global install automatically.

Switching prefix mode

If you installed gstack with one prefix setting and want to switch:

cd .claude/skills/gstack && ./setup --no-prefix   # switch to /qa, /ship
cd .claude/skills/gstack && ./setup --prefix       # switch to /gstack-qa, /gstack-ship

Setup cleans up the old symlinks automatically. No manual cleanup needed. Only entries gstack created are removed: a skill of your own that shares a name (a hand-written qa/, say) is left in place and named in setup's final summary.

Alternative: point your global install at a branch

If you don't want per-project symlinks, you can switch the global install:

cd ~/.claude/skills/gstack
git fetch origin
git checkout origin/<branch>
bun install && bun run build && ./setup

This affects all projects. To revert: git checkout main && git pull && bun run build && ./setup.

Community PR triage (wave process)

When community PRs accumulate, batch them into themed waves:

1. Categorize — group by theme (security, features, infra, docs)
2. Deduplicate — if two PRs fix the same thing, pick the one that changes fewer lines. Close the other with a note pointing to the winner.
3. Collector branch — create pr-wave-N, merge clean PRs, resolve conflicts for dirty ones, verify with bun run test && bun run build
4. Close with context — every closed PR gets a comment explaining why and what (if anything) supersedes it. Contributors did real work; respect that with clear communication.
5. Ship as one PR — single PR to main with all attributions preserved in merge commits. Include a summary table of what merged and what closed.

See PR #205 (v0.8.3) for the first wave as an example.

Upgrade migrations

When a release changes on-disk state (directory structure, config format, stale files) in ways that ./setup alone can't fix, add a migration script so existing users get a clean upgrade.

When to add a migration

• Changed how skill directories are created (symlinks vs real dirs)
• Renamed or moved config keys in ~/.gstack/config.yaml
• Need to delete orphaned files from a previous version
• Changed the format of ~/.gstack/ state files

Don't add a migration for: new features (users get them automatically), new skills (setup discovers them), or code-only changes (no on-disk state).

How to add one

1. Create gstack-upgrade/migrations/v{VERSION}.sh where {VERSION} matches the VERSION file for the release that needs the fix.
2. Make it executable: chmod +x gstack-upgrade/migrations/v{VERSION}.sh
3. The script must be idempotent (safe to run multiple times) and non-fatal (failures are logged but don't block the upgrade).
4. Include a comment block at the top explaining what changed, why the migration is needed, and which users are affected.

Example:

#!/usr/bin/env bash
# Migration: v0.15.2.0 — Fix skill directory structure
# Affected: users who installed with --no-prefix before v0.15.2.0
set -euo pipefail
SCRIPT_DIR="$(cd "$(dirname "$0")/../.." && pwd)"
"$SCRIPT_DIR/bin/gstack-relink" 2>/dev/null || true

How it runs

During /gstack-upgrade, after ./setup completes (Step 4.75), the upgrade skill scans gstack-upgrade/migrations/ and runs every v*.sh script whose version is newer than the user's old version. Scripts run in version order. Failures are logged but never block the upgrade.

Testing migrations

Migrations are tested as part of bun run test (tier 1, free). The test suite verifies that all migration scripts in gstack-upgrade/migrations/ are executable and parse without syntax errors.

Shipping your changes

When you're happy with your skill edits:

/ship

This runs tests, reviews the diff, triages Greptile comments (with 2-tier escalation), manages TODOS.md, bumps the version, and opens a PR. See ship/SKILL.md for the full workflow.