docs: add README and CLAUDE.md

README with open source install instructions (project-level and user-level),
copy-paste CLAUDE.md snippet for users, command reference, and architecture.
CLAUDE.md with dev workflow for contributors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

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+# gstack-browse development
+
+## Commands
+
+```bash
+bun install          # install dependencies
+bun test             # run integration tests (40 tests with fixture server)
+bun run dev <cmd>    # run CLI in dev mode, e.g. bun run dev goto https://example.com
+bun run build        # compile binary to dist/browse
+```
+
+## Deploying to the active skill
+
+The active skill lives at `~/.claude/skills/gstack-browse/`. After making changes:
+
+1. Push your branch
+2. Pull in the skill directory: `cd ~/.claude/skills/gstack-browse && git pull`
+3. Rebuild: `cd ~/.claude/skills/gstack-browse && bun run build`
+
+Or copy the binary directly: `cp dist/browse ~/.claude/skills/gstack-browse/dist/browse`

README.md

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+# gstack-browse
+
+Fast headless browser for Claude Code. Persistent Chromium daemon with ~100ms commands.
+
+Navigate pages, read content, click elements, fill forms, run JavaScript, take screenshots, inspect CSS/DOM, capture console/network logs. No MCP server, no Chrome extension — just a fast CLI that Claude calls via Bash.
+
+Created by [Garry Tan](https://x.com/garrytan), President & CEO of [Y Combinator](https://www.ycombinator.com/) and founder of [Garry's List](https://garryslist.org).
+
+## Why
+
+Claude Code needs to browse the web — check deployments, read docs, verify UI changes, test forms. Existing options (MCP servers, Chrome extensions) are slow, flaky, or require complex setup.
+
+gstack-browse is different:
+- **Fast**: persistent Chromium daemon, ~100ms per command after first call
+- **Simple**: single CLI binary, auto-starts on first use, auto-shuts down after 30 min
+- **Reliable**: no WebSocket fragility, no extension permissions, just HTTP to a local server
+- **Zero config**: clone, build, done
+
+## Install
+
+### Prerequisites
+
+- [Bun](https://bun.sh/) v1.0+
+
+### Option A: Project-level (recommended for teams)
+
+Install into your repo so every contributor gets it automatically:
+
+```bash
+cd your-repo
+git submodule add https://github.com/garrytan/gstack-browse.git .claude/skills/gstack-browse
+cd .claude/skills/gstack-browse
+bun install && bun run build
+```
+
+Commit the submodule. Anyone who clones your repo gets the skill.
+
+### Option B: User-level (personal)
+
+Install once, available across all your projects:
+
+```bash
+git clone https://github.com/garrytan/gstack-browse.git ~/.claude/skills/gstack-browse
+cd ~/.claude/skills/gstack-browse
+bun install && bun run build
+```
+
+### Verify
+
+```bash
+# Project-level:
+.claude/skills/gstack-browse/dist/browse --help
+
+# User-level:
+~/.claude/skills/gstack-browse/dist/browse --help
+```
+
+## Teach Claude to use it
+
+Add this to your project's `CLAUDE.md` so Claude knows the skill is available:
+
+````markdown
+## Web browsing
+
+Use gstack-browse for all web browsing tasks. It's a fast headless browser CLI.
+
+```bash
+# Set the path (project-level install):
+B=.claude/skills/gstack-browse/dist/browse
+# Or user-level install:
+# B=~/.claude/skills/gstack-browse/dist/browse
+
+# Navigate and read
+$B goto https://example.com
+$B text                          # cleaned page text
+$B html "main"                   # innerHTML of element
+$B links                         # all links as "text -> href"
+
+# Interact
+$B click "button.submit"
+$B fill "#email" "test@test.com"
+$B select "#country" "US"
+$B wait ".loaded"                # wait for element (max 10s)
+
+# Inspect
+$B js "document.title"           # run JavaScript
+$B css "body" "font-family"      # computed CSS
+$B console                       # captured console messages
+$B network                       # captured network requests
+$B screenshot /tmp/page.png      # take screenshot
+
+# Tabs
+$B tabs                          # list open tabs
+$B newtab https://other.com      # open new tab
+$B tab 2                         # switch to tab
+
+# Multi-step (single call)
+echo '[["goto","https://example.com"],["fill","#email","test@test.com"],["click","#submit"]]' | $B chain
+```
+
+Navigate once, then query many times — goto loads the page, everything else runs against it instantly.
+````
+
+## Quick reference
+
+| Category | Commands |
+|----------|----------|
+| Navigate | `goto <url>`, `back`, `forward`, `reload`, `url` |
+| Read | `text`, `html [sel]`, `links`, `forms`, `accessibility` |
+| Interact | `click <sel>`, `fill <sel> <val>`, `select <sel> <val>`, `hover <sel>`, `type <text>`, `press <key>`, `scroll [sel]`, `wait <sel>`, `viewport <WxH>` |
+| Inspect | `js <expr>`, `eval <file>`, `css <sel> <prop>`, `attrs <sel>`, `console`, `network`, `cookies`, `storage`, `perf` |
+| Visual | `screenshot [path]`, `pdf [path]`, `responsive [prefix]` |
+| Compare | `diff <url1> <url2>` |
+| Tabs | `tabs`, `tab <id>`, `newtab [url]`, `closetab [id]` |
+| Server | `status`, `stop`, `restart` |
+
+See [SKILL.md](SKILL.md) for the full command reference with examples.
+
+## Architecture
+
+```
+Claude Code ──Bash──> browse CLI ──HTTP──> Bun server ──Playwright──> Chromium
+                         |                     |
+                    thin client           persistent daemon
+                  (sends commands)      (port 9400-9410, auto-start,
+                                         30 min idle shutdown)
+```
+
+- CLI reads `/tmp/browse-server.json` for server port + auth token
+- If no server running, CLI auto-starts one in the background (~3s)
+- All commands go over HTTP POST with bearer token auth
+- Chromium crash or idle timeout kills the server; next CLI call restarts it
+
+## Development
+
+```bash
+bun install              # install dependencies
+bun test                 # run 40 integration tests
+bun run dev <cmd>        # run CLI without compiling
+bun run build            # compile to dist/browse
+```
+
+## License
+
+MIT