gstack

name	gstack
version	1.1.0
description	Fast headless browser for QA testing and site dogfooding. Navigate any URL, interact with elements, verify page state, diff before/after actions, take annotated screenshots, check responsive layouts, test forms and uploads, handle dialogs, and assert element states. ~100ms per command. Use when you need to test a feature, verify a deployment, dogfood a user flow, or file a bug with evidence.
allowed-tools	["Bash","Read","AskUserQuestion"]

Preamble (run first)

_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)
_BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
echo "BRANCH: $_BRANCH"

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. Re-ground: State the project, the current branch (use the _BRANCH value printed by the preamble — NOT any branch from conversation history or gitStatus), and the current plan/task. (1-2 sentences)
2. Simplify: Explain the problem in plain English a smart 16-year-old could follow. No raw function names, no internal jargon, no implementation details. Use concrete examples and analogies. Say what it DOES, not what it's called.
3. Recommend: RECOMMENDATION: Choose [X] because [one-line reason]
4. Options: Lettered options: A) ... B) ... C) ...

Assume the user hasn't looked at this window in 20 minutes and doesn't have the code open. If you'd need to read the source to understand your own explanation, it's too complex.

Per-skill instructions may add additional formatting rules on top of this baseline.

Contributor Mode

If _CONTRIB is true: you are in contributor mode. You're a gstack user who also helps make it better.

At the end of each major workflow step (not after every single command), reflect on the gstack tooling you used. Rate your experience 0 to 10. If it wasn't a 10, think about why. If there is an obvious, actionable bug OR an insightful, interesting thing that could have been done better by gstack code or skill markdown — file a field report. Maybe our contributor will help make us better!

Calibration — this is the bar: For example, $B js "await fetch(...)" used to fail with SyntaxError: await is only valid in async functions because gstack didn't wrap expressions in async context. Small, but the input was reasonable and gstack should have handled it — that's the kind of thing worth filing. Things less consequential than this, ignore.

NOT worth filing: user's app bugs, network errors to user's URL, auth failures on user's site, user's own JS logic bugs.

To file: write ~/.gstack/contributor-logs/{slug}.md with all sections below (do not truncate — include every section through the Date/Version footer):

# {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}
**My rating:** {0-10} — {one sentence on why it wasn't a 10}

## Steps to reproduce
1. {step}

## Raw output

{paste the actual error or unexpected output here}

## What would make this a 10
{one sentence: what gstack should have done differently}

**Date:** {YYYY-MM-DD} | **Version:** {gstack version} | **Skill:** /{skill}

Slug: lowercase, hyphens, max 60 chars (e.g. browse-js-no-await). 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}"

gstack browse: QA Testing & Dogfooding

Persistent headless Chromium. First call auto-starts (~3s), then ~100-200ms per command. Auto-shuts down after 30 min idle. State persists between calls (cookies, tabs, sessions).

SETUP (run this check BEFORE any browse command)

_ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
B=""
[ -n "$_ROOT" ] && [ -x "$_ROOT/.claude/skills/gstack/browse/dist/browse" ] && B="$_ROOT/.claude/skills/gstack/browse/dist/browse"
[ -z "$B" ] && B=~/.claude/skills/gstack/browse/dist/browse
if [ -x "$B" ]; then
  echo "READY: $B"
else
  echo "NEEDS_SETUP"
fi

If NEEDS_SETUP:

1. Tell the user: "gstack browse needs a one-time build (~10 seconds). OK to proceed?" Then STOP and wait.
2. Run: cd <SKILL_DIR> && ./setup
3. If bun is not installed: curl -fsSL https://bun.sh/install | bash

IMPORTANT

• Use the compiled binary via Bash: $B <command>
• NEVER use mcp__claude-in-chrome__* tools. They are slow and unreliable.
• Browser persists between calls — cookies, login sessions, and tabs carry over.
• Dialogs (alert/confirm/prompt) are auto-accepted by default — no browser lockup.

QA Workflows

Test a user flow (login, signup, checkout, etc.)

# 1. Go to the page
$B goto https://app.example.com/login

# 2. See what's interactive
$B snapshot -i

# 3. Fill the form using refs
$B fill @e3 "[e-mail]"
$B fill @e4 "password123"
$B click @e5

# 4. Verify it worked
$B snapshot -D              # diff shows what changed after clicking
$B is visible ".dashboard"  # assert the dashboard appeared
$B screenshot /tmp/after-login.png

Verify a deployment / check prod

$B goto https://yourapp.com
$B text                          # read the page — does it load?
$B console                       # any JS errors?
$B network                       # any failed requests?
$B js "document.title"           # correct title?
$B is visible ".hero-section"    # key elements present?
$B screenshot /tmp/prod-check.png

Dogfood a feature end-to-end

# Navigate to the feature
$B goto https://app.example.com/new-feature

# Take annotated screenshot — shows every interactive element with labels
$B snapshot -i -a -o /tmp/feature-annotated.png

# Find ALL clickable things (including divs with cursor:pointer)
$B snapshot -C

# Walk through the flow
$B snapshot -i          # baseline
$B click @e3            # interact
$B snapshot -D          # what changed? (unified diff)

# Check element states
$B is visible ".success-toast"
$B is enabled "#next-step-btn"
$B is checked "#agree-checkbox"

# Check console for errors after interactions
$B console

Test responsive layouts

# Quick: 3 screenshots at mobile/tablet/desktop
$B goto https://yourapp.com
$B responsive /tmp/layout

# Manual: specific viewport
$B viewport 375x812     # iPhone
$B screenshot /tmp/mobile.png
$B viewport 1440x900    # Desktop
$B screenshot /tmp/desktop.png

# Element screenshot (crop to specific element)
$B screenshot "#hero-banner" /tmp/hero.png
$B snapshot -i
$B screenshot @e3 /tmp/button.png

# Region crop
$B screenshot --clip 0,0,800,600 /tmp/above-fold.png

# Viewport only (no scroll)
$B screenshot --viewport /tmp/viewport.png

Test file upload

$B goto https://app.example.com/upload
$B snapshot -i
$B upload @e3 /path/to/test-file.pdf
$B is visible ".upload-success"
$B screenshot /tmp/upload-result.png

Test forms with validation

$B goto https://app.example.com/form
$B snapshot -i

# Submit empty — check validation errors appear
$B click @e10                        # submit button
$B snapshot -D                       # diff shows error messages appeared
$B is visible ".error-message"

# Fill and resubmit
$B fill @e3 "valid input"
$B click @e10
$B snapshot -D                       # diff shows errors gone, success state

Test dialogs (delete confirmations, prompts)

# Set up dialog handling BEFORE triggering
$B dialog-accept              # will auto-accept next alert/confirm
$B click "#delete-button"     # triggers confirmation dialog
$B dialog                     # see what dialog appeared
$B snapshot -D                # verify the item was deleted

# For prompts that need input
$B dialog-accept "my answer"  # accept with text
$B click "#rename-button"     # triggers prompt

Test authenticated pages (import real browser cookies)

# Import cookies from your real browser (opens interactive picker)
$B cookie-import-browser

# Or import a specific domain directly
$B cookie-import-browser comet --domain .github.com

# Now test authenticated pages
$B goto https://github.com/settings/profile
$B snapshot -i
$B screenshot /tmp/github-profile.png

Compare two pages / environments

$B diff https://staging.app.com https://prod.app.com

Multi-step chain (efficient for long flows)

echo '[
  ["goto","https://app.example.com"],
  ["snapshot","-i"],
  ["fill","@e3","[e-mail]"],
  ["fill","@e4","password"],
  ["click","@e5"],
  ["snapshot","-D"],
  ["screenshot","/tmp/result.png"]
]' | $B chain

Quick Assertion Patterns

# Element exists and is visible
$B is visible ".modal"

# Button is enabled/disabled
$B is enabled "#submit-btn"
$B is disabled "#submit-btn"

# Checkbox state
$B is checked "#agree"

# Input is editable
$B is editable "#name-field"

# Element has focus
$B is focused "#search-input"

# Page contains text
$B js "document.body.textContent.includes('Success')"

# Element count
$B js "document.querySelectorAll('.list-item').length"

# Specific attribute value
$B attrs "#logo"    # returns all attributes as JSON

# CSS property
$B css ".button" "background-color"

Snapshot System

The snapshot is your primary tool for understanding and interacting with pages.

-i        --interactive           Interactive elements only (buttons, links, inputs) with @e refs
-c        --compact               Compact (no empty structural nodes)
-d <N>    --depth                 Limit tree depth (0 = root only, default: unlimited)
-s <sel>  --selector              Scope to CSS selector
-D        --diff                  Unified diff against previous snapshot (first call stores baseline)
-a        --annotate              Annotated screenshot with red overlay boxes and ref labels
-o <path> --output                Output path for annotated screenshot (default: /tmp/browse-annotated.png)
-C        --cursor-interactive    Cursor-interactive elements (@c refs — divs with pointer, onclick)

All flags can be combined freely. -o only applies when -a is also used. Example: $B snapshot -i -a -C -o /tmp/annotated.png

Ref numbering: @e refs are assigned sequentially (@e1, @e2, ...) in tree order. @c refs from -C are numbered separately (@c1, @c2, ...).

After snapshot, use @refs as selectors in any command:

$B click @e3       $B fill @e4 "value"     $B hover @e1
$B html @e2        $B css @e5 "color"      $B attrs @e6
$B click @c1       # cursor-interactive ref (from -C)

Output format: indented accessibility tree with @ref IDs, one element per line.

  @e1 [heading] "Welcome" [level=1]
  @e2 [textbox] "Email"
  @e3 [button] "Submit"

Refs are invalidated on navigation — run snapshot again after goto.

Command Reference

Navigation

Command	Description
back	History back
forward	History forward
goto <url>	Navigate to URL
reload	Reload page
url	Print current URL

Reading

Command	Description
accessibility	Full ARIA tree
forms	Form fields as JSON
html [selector]	innerHTML of selector (throws if not found), or full page HTML if no selector given
links	All links as "text → href"
text	Cleaned page text

Interaction

Command	Description
click <sel>	Click element
cookie <name>=<value>	Set cookie on current page domain
cookie-import <json>	Import cookies from JSON file
cookie-import-browser [browser] [--domain d]	Import cookies from Comet, Chrome, Arc, Brave, or Edge (opens picker, or use --domain for direct import)
dialog-accept [text]	Auto-accept next alert/confirm/prompt. Optional text is sent as the prompt response
dialog-dismiss	Auto-dismiss next dialog
fill <sel> <val>	Fill input
header <name>:<value>	Set custom request header (colon-separated, sensitive values auto-redacted)
hover <sel>	Hover element
press <key>	Press key — Enter, Tab, Escape, ArrowUp/Down/Left/Right, Backspace, Delete, Home, End, PageUp, PageDown, or modifiers like Shift+Enter
scroll [sel]	Scroll element into view, or scroll to page bottom if no selector
select <sel> <val>	Select dropdown option by value, label, or visible text
type <text>	Type into focused element
upload <sel> <file> [file2...]	Upload file(s)
useragent <string>	Set user agent
viewport <WxH>	Set viewport size
`wait <sel	--networkidle

Inspection

Command	Description
`attrs <sel	@ref>`
`console [--clear	--errors]`
cookies	All cookies as JSON
css <sel> <prop>	Computed CSS value
dialog [--clear]	Dialog messages
eval <file>	Run JavaScript from file and return result as string (path must be under /tmp or cwd)
is <prop> <sel>	State check (visible/hidden/enabled/disabled/checked/editable/focused)
js <expr>	Run JavaScript expression and return result as string
network [--clear]	Network requests
perf	Page load timings
storage [set k v]	Read all localStorage + sessionStorage as JSON, or set to write localStorage

Visual

Command	Description
diff <url1> <url2>	Text diff between pages
pdf [path]	Save as PDF
responsive [prefix]	Screenshots at mobile (375x812), tablet (768x1024), desktop (1280x720). Saves as {prefix}-mobile.png etc.
`screenshot [--viewport] [--clip x,y,w,h] [selector	@ref] [path]`

Snapshot

Command	Description
snapshot [flags]	Accessibility tree with @e refs for element selection. Flags: -i interactive only, -c compact, -d N depth limit, -s sel scope, -D diff vs previous, -a annotated screenshot, -o path output, -C cursor-interactive @c refs

Meta

Command	Description
chain	Run commands from JSON stdin. Format: [["cmd","arg1",...],...]

Tabs

Command	Description
closetab [id]	Close tab
newtab [url]	Open new tab
tab <id>	Switch to tab
tabs	List open tabs

Server

Command	Description
restart	Restart server
status	Health check
stop	Shutdown server

Tips

1. Navigate once, query many times. goto loads the page; then text, js, screenshot all hit the loaded page instantly.
2. Use snapshot -i first. See all interactive elements, then click/fill by ref. No CSS selector guessing.
3. Use snapshot -D to verify. Baseline → action → diff. See exactly what changed.
4. Use is for assertions. is visible .modal is faster and more reliable than parsing page text.
5. Use snapshot -a for evidence. Annotated screenshots are great for bug reports.
6. Use snapshot -C for tricky UIs. Finds clickable divs that the accessibility tree misses.
7. Check console after actions. Catch JS errors that don't surface visually.
8. Use chain for long flows. Single command, no per-step CLI overhead.