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gstack

Fast headless browser for QA testing and site dogfooding.

Skill by VanL

IndexedMIT
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Works with Claude Code, Claude apps, Codex, Cursor, Gemini CLI, GitHub Copilot, VS Code, OpenCode, Goose, Windsurf. Read the repository before you give any tool access to your data.

npx agentmarket install skill/vanl-gstack

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About

Fast headless browser for QA testing and site dogfooding. Navigate pages, interact with elements, verify state, diff before/after, take annotated screenshots, test responsive layouts, forms, uploads, dialogs, and capture bug evidence. Use when asked to open or test a site, verify a deployment, dogfood a user flow, or file a bug with screenshots. (gstack)

Use cases: testing

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What this skill can do and what it asks for, from its SKILL.md. Checked Oct 25, 2026.

Tools
No tools found
Secrets
None asked for
Install scripts
None found
Runs as
Node.js package

Network hosts it talks to 1

  • codeload.github.com · found in install command

Files it touches

  • ~/.claude/skills/gstack

What's inside

Skill name
gstack
Description
Fast headless browser for QA testing and site dogfooding. Navigate pages, interact with elements, verify state, diff before/after, take annotated screenshots, test responsive layouts, forms, uploads, dialogs, and capture bug evidence. Use when asked to open or test a site, verify a deployment, dogfood a user flow, or file a bug with screenshots. (gstack)
License
MIT
Instructions
944 lines in SKILL.md · view on GitHub

Before installing

  • Ships executable scripts
  • Instructions call the network

Agent Skills spec issues

  • allowed-tools: must be a space-separated string
  • body: 944 lines (spec recommends under 500)

Files (200)

  • .env.example
  • .gitattributes
  • actionlint.yaml · .github/
  • Dockerfile.ci · .github/docker/
  • actionlint.yml · .github/workflows/
  • ci-image.yml · .github/workflows/
  • evals-periodic.yml · .github/workflows/
  • evals.yml · .github/workflows/
  • make-pdf-gate.yml · .github/workflows/
  • pr-title-sync.yml · .github/workflows/
  • skill-docs.yml · .github/workflows/
  • version-gate.yml · .github/workflows/
  • windows-free-tests.yml · .github/workflows/
  • .gitignore
  • .gitlab-ci.yml
  • AGENTS.md
  • ARCHITECTURE.md
  • BROWSER.md
  • CHANGELOG.md
  • CLAUDE.md
  • CONTRIBUTING.md
  • DESIGN.md
  • ETHOS.md
  • LICENSE
  • README.md
  • SKILL.md
  • SKILL.md.tmpl
  • TODOS.md
  • USING_GBRAIN_WITH_GSTACK.md
  • VERSION
  • actionlint.yaml
  • openai.yaml · agents/
  • SKILL.md · autoplan/
  • SKILL.md.tmpl · autoplan/
  • SKILL.md · benchmark-models/
  • SKILL.md.tmpl · benchmark-models/
  • SKILL.md · benchmark/
  • SKILL.md.tmpl · benchmark/
  • chrome-cdp · bin/
  • dev-setup · bin/
  • dev-teardown · bin/
  • gstack-analytics · bin/
  • gstack-artifacts-init · bin/
  • gstack-artifacts-url · bin/
  • gstack-brain-consumer · bin/
  • gstack-brain-context-load.ts · bin/
  • gstack-brain-enqueue · bin/
  • gstack-brain-reader · bin/
  • gstack-brain-restore · bin/
  • gstack-brain-sync · bin/
  • gstack-brain-uninstall · bin/
  • gstack-builder-profile · bin/
  • gstack-codex-probe · bin/
  • gstack-community-dashboard · bin/
  • gstack-config · bin/
  • gstack-developer-profile · bin/
  • gstack-diff-scope · bin/
  • gstack-extension · bin/
  • gstack-gbrain-detect · bin/
  • gstack-gbrain-install · bin/
  • …and 140 more

SKILL.md (first lines)

<!-- AUTO-GENERATED from SKILL.md.tmpl — do not edit directly -->
<!-- Regenerate: bun run gen:skill-docs -->

## 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=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
find ~/.gstack/sessions -mmin +120 -type f -exec rm {} + 2>/dev/null || true
_PROACTIVE=$(~/.claude/skills/gstack/bin/gstack-config get proactive 2>/dev/null || echo "true")
_PROACTIVE_PROMPTED=$([ -f ~/.gstack/.proactive-prompted ] && echo "yes" || echo "no")
_BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
echo "BRANCH: $_BRANCH"
_SKILL_PREFIX=$(~/.claude/skills/gstack/bin/gstack-config get skill_prefix 2>/dev/null || echo "false")
echo "PROACTIVE: $_PROACTIVE"
echo "PROACTIVE_PROMPTED: $_PROACTIVE_PROMPTED"
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: $REPO_MODE"
_LAKE_SEEN=$([ -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)
_TEL_PROMPTED=$([ -f ~/.gstack/.telemetry-prompted ] && echo "yes" || echo "no")
_TEL_START=$(date +%s)
_SESSION_ID="$$-$(date +%s)"
echo "TELEMETRY: ${_TEL:-off}"
echo "TEL_PROMPTED: $_TEL_PROMPTED"
_EXPLAIN_LEVEL=$(~/.claude/skills/gstack/bin/gstack-config get explain_level 2>/dev/null || echo "default")
if [ "$_EXPLAIN_LEVEL" != "default" ] && [ "$_EXPLAIN_LEVEL" != "terse" ]; then _EXPLAIN_LEVEL="default"; fi
echo "EXPLAIN_LEVEL: $_EXPLAIN_LEVEL"
_QUESTION_TUNING=$(~/.claude/skills/gstack/bin/gstack-config get question_tuning 2>/dev/null || echo "false")
echo "QUESTION_TUNING: $_QUESTION_TUNING"
mkdir -p ~/.gstack/analytics
if [ "$_TEL" != "off" ]; then
echo '{"skill":"gstack","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null || echo "unknown")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
fi
for _PF in $(find ~/.gstack/analytics -maxdepth 1 -name '.pending-*' 2>/dev/null); do
  if [ -f "$_PF" ]; then
    if [ "$_TEL" != "off" ] && [ -x "~/.claude/skills/gstack/bin/gstack-telemetry-log" ]; then
      ~/.claude/skills/gstack/bin/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true
    fi
    rm -f "$_PF" 2>/dev/null || true
  fi
  break
done
eval "$(~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null)" 2>/dev/null || true
_LEARN_FILE="${GSTACK_HOME:-$HOME/.gstack}/projects/${SLUG:-unknown}/learnings.jsonl"
if [ -f "$_LEARN_FILE" ]; then
  _LEARN_COUNT=$(wc -l < "$_LEARN_FILE" 2>/dev/null | tr -d ' ')
  echo "LEARNINGS: $_LEARN_COUNT entries loaded"
  if [ "$_LEARN_COUNT" -gt 5 ] 2>/dev/null; then
    ~/.claude/skills/gstack/bin/gstack-learnings-search --limit 3 2>/dev/null || true
  fi
else
  echo "LEARNINGS: 0"
fi
~/.claude/skills/gstack/bin/gstack-timeline-log '{"skill":"gstack","event":"started","branch":"'"$_BRANCH"'","session":"'"$_SESSION_ID"'"}' 2>/dev/null &
_HAS_ROUTING="no"
if [ -f CLAUDE.md ] && grep -q "## Skill routing" CLAUDE.md 2>/dev/null; then
  _HAS_ROUTING="yes"
fi
_ROUTING_DECLINED=$(~/.claude/skills/gstack/bin/gstack-config get routing_declined 2>/dev/null || echo "false")
echo "HAS_ROUTING: $_HAS_ROUTING"
echo "ROUTING_DECLINED: $_ROUTING_DECLINED"
_VENDORED="no"
if [ -d ".claude/skills/gstack" ] && [ ! -L ".claude/skills/gstack" ]; then
  if [ -f ".claude/skills/gstack/VERSION" ] || [ -d ".claude/skills/gstack/.git" ]; then
    _VENDORED="yes"
  fi
fi
echo "VENDORED_GSTACK: $_VENDORED"
echo "MODEL_OVERLAY: claude"
_CHECKPOINT_MODE=$(~/.claude/skills/gstack/bin/gstack-config get checkpoint_mode 2>/dev/null || echo "explicit")
_CHECKPOINT_PUSH=$(~/.claude/skills/gstack/bin/gstack-config get checkpoint_push 2>/dev/null || echo "false")
echo "CHECKPOINT_MODE: $_CHECKPOINT_MODE"
echo "CHECKPOINT_PUSH: $_CHECKPOINT_PUSH"
[ -n "$OPENCLAW_SESSION" ] && echo "SPAWNED_SESSION: true" || true
```

## Plan Mode Safe Operations

In plan mode, allowed because they inform the plan: `$B`, `$D`, `codex exec`/`codex review`, writes to `~/.gstack/`, writes to the plan file, and `open` for generated artifacts.

## 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, fall back to writing the decision brief into the plan file as a `## Decisions to confirm` section + ExitPlanMode — never silently auto-decide. 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?"

If `SKILL_PREFIX` is `"true"`, suggest/invoke `/gstack-*` names. Disk paths stay `~/.claude/skills/gstack/[skill-name]/SKILL.md`.

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 output shows `JUST_UPGRADED <from> <to>`: print "Running gstack v{to} (just updated!)". If `SPAWNED_SESSION` is true, skip feature discovery.

Feature discovery, max one prompt per session:
- Missing `~/.claude/skills/gstack/.feature-prompted-continuous-checkpoint`: AskUserQuestion for Continuous checkpoint auto-commits. If accepted, run `~/.claude/skills/gstack/bin/gstack-config set checkpoint_mode continuous`. Always touch marker.
- Missing `~/.claude/skills/gstack/.feature-prompted-model-overlay`: inform "Model overlays are active. MODEL_OVERLAY shows the patch." Always touch marker.

After upgrade prompts, continue workflow.

If `WRITING_STYLE_PENDING` is `yes`: ask once about writing style:

> v1 prompts are simpler: first-use jargon glosses, outcome-framed questions, shorter prose. Keep default or restore terse?

Options:
- A) Keep the new default (recommended — good writing helps everyone)
- B) Restore V0 prose — set `explain_level: terse`

If A: leave `explain_level` unset (defaults to `default`).
If B: run `~/.claude/skills/gstack/bin/gstack-config set explain_level terse`.

Always run (regardless of choice):
```bash
rm -f ~/.gstack/.writing-style-prompt-pending
touch ~/.gstack/.writing-style-prompted

From VanL/engram, MIT.

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Last commit (this folder)
Jun 30, 2026 (4 months ago)
Last release
Jul 1, 2026 (4 months ago)

From GitHub (fetched Oct 24, 2026).

Details

License
MIT
First seen
Oct 24, 2026
Last checked
Oct 24, 2026

More from VanL

Cite this page

gstack skill. Agent Mart. https://agentmart.dev/skills/vanl-gstack (last updated 2026-10-24)