Taprun

Browser automation that runs in your Chrome, not someone else's cloud.

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Local-first browser automation. Compile once, run forever at zero LLM tokens.

Point Taprun at any site. Your AI agent inspects the page once and emits a deterministic .plan.json program. Replay it forever — same result every call, $0 in tokens. Cookies and login sessions stay in your real Chrome — by architecture, not policy. tap verify catches breakage before your data goes stale.

Works with Claude Code, Cursor, Cline, Windsurf, and any MCP host. 70+ pre-built taps, or forge your own from any URL.

Capture: AI inspects the site → compiles a .plan.json program     (one-time cost)
Run:     The program executes instantly, same result every time   ($0, zero AI)
Verify:  tap verify checks the snapshot equivalence predicate     (catches drift)
Repair:  re-run capture against the same site/name; the next      (only when needed)
         verify rebaselines after human review

How Taprun Compares

	Taprun	AI Browser Agents	Traditional Scrapers
AI cost per run	$0 (compile once)	Tokens every run	Free
Accuracy	Deterministic	Varies per run	Deterministic
Silent failure detection	Per-tap CEL snapshot_equivalent predicate + 4-arm verdict	None	None
Breakage diagnostics	tap verify — exact diff of what changed	None	Manual spot checks
Detection risk	Low (real browser sessions)	High	High
Runtimes	2 (Chrome extension + Playwright)	1	1
Code inspectable	.plan.json — bare JSON, 11-op closed vocabulary, git diff	Black box / ephemeral	Fragile scripts
MCP native	Yes (authoring layer only — execution is zero tokens)	No	No

Get Started

1. Install

Zero-install via npx (any machine with Node):

npx -y @taprun/cli --version

The first run downloads the matching platform binary (~30MB) and caches it. Subsequent calls are instant.

Permanent install via curl (macOS / Linux):

curl -fsSL https://taprun.dev/install.sh | sh

Or via Homebrew (macOS / Linux):

brew install LeonTing1010/tap/taprun

Platform	Download
macOS (Apple Silicon)	tap-macos-arm64
macOS (Intel)	tap-macos-x64
Linux	tap-linux-x64
Windows	tap-windows-x64.exe

2. Connect to Your AI Agent

Works with Claude Code, Cursor, Windsurf, or any MCP-compatible agent — no extension needed:

{ "mcpServers": { "tap": { "command": "npx", "args": ["-y", "@taprun/cli", "mcp", "stdio"] } } }

Or run the server directly:

tap mcp stdio    # default; pipe to your MCP host
tap mcp http     # streamable-HTTP on 127.0.0.1:7891 (bearer auth)

3. Go

tap github/trending              # GitHub trending repos
tap hackernews/hot               # Hacker News front page
tap weibo/hot                    # 微博热搜
tap xiaohongshu/search --keyword "AI"  # 小红书搜索

Or just ask your AI agent:

You:   What's trending on GitHub today?
Agent: Here are today's top repos — React compiler hit 734 stars...

You:   Capture a tap for Douban top 250 movies
Agent: Done. Run `tap douban/top250` anytime — $0 per run.

Optional: Chrome Extension (for login-required sites)

Most taps work without login. For sites that need your session (Xiaohongshu, Zhihu, etc.), install the Chrome Extension from the Chrome Web Store.

Optional: Embed in your agent code (TypeScript / Python)

Skip MCP — call the tap binary from your own loop:

tap hackernews/top --args '{}'    # JSON-on-stdout, exit 0 on success
tap verify hackernews/top         # 4-arm verdict (equivalent / drifted / first_snapshot / unreachable)
tap capture <url> hackernews/top --intent "front-page top stories"

The CLI emits ToolResult<T> envelopes as JSON — same shape the MCP surface returns — so any language with a subprocess library can drive it. See tap --help for the full verb list.

Have an existing Playwright / Puppeteer / Stagehand script?

Don't rewrite. Convert with one of the open-source adapters — drop your existing source in, get a Tap-compatible .plan.json plan out:

# Existing Playwright script (47M weekly npm downloads — most likely the one you have)
npm install @taprun/from-playwright @taprun/spec
node -e "import('@taprun/from-playwright').then(m => console.log(m.playwrightToTap(require('fs').readFileSync('tests/login.spec.ts','utf8'), {site:'example', name:'login'})))"

# Or scaffold a new starter from scratch
npx create-tap-script github/trending https://github.com/trending

Adapter	Source format	Coverage
@taprun/from-playwright	.ts/.js Playwright tests	8 page.* APIs (goto/click/fill/type/press/waitForSelector/waitForTimeout/screenshot)
@taprun/from-puppeteer	.ts/.js Puppeteer scripts	7 page.* APIs + page.keyboard.press
@taprun/from-stagehand	.ts/.js Stagehand scripts	Hybrid: deterministic page.* mapped to plan ops; NL act/extract/observe flagged for honest verify verdicts
create-tap-script	(none — scaffolder)	Generates a starter .plan.json envelope from <site>/<name> <url>

The format itself is documented at @taprun/spec — the public protocol surface package: TypeScript types for the v2 Plan (11-op closed union + discriminated read/write Plan union) + JSON Schema 2020-12 with $id resolvable at taprun.dev/spec/plan-v1/schema.json, bidirectionally drift-guarded against the TS types. Third-party tooling (IDE $schema autocomplete, ajv-equivalent validators in Python/Ruby/Go, governance layers, alternative runtimes, MCP hosts with plan-aware permission scoping) builds against this package without depending on the proprietary Tap engine. Plan-v1 reference: taprun.dev/spec/plan-v1. Source for all five packages: packages/ (see packages/README.md for the workspace overview).

What Can You Do?

Read — Extract data from any website

tap reddit/hot                   # Reddit front page
tap bilibili/trending            # Bilibili trending
tap arxiv/search --keyword "LLM" # arXiv papers

Write — Operate any website

tap xiaohongshu/publish --title "My Note" --images photo.jpg
tap zhihu/publish --title "My Article" --content "..."

Watch — Monitor changes

tap verify github/trending        # spot drift; schedule via cron / launchd

Compose — Chain like Unix pipes

tap github/trending | tap filter --field stars --gt 500 | tap table

Forge — Create new automations with AI

tap capture https://news.ycombinator.com hackernews/hot --intent "top stories"   # API detected — compiled without AI
tap capture https://example.com mysite/home --intent "..."                       # BYOK Claude / GPT for the long tail

Bring your own model — works with Claude, OpenAI, DeepSeek, or any OpenAI-compatible endpoint including local Ollama / LM Studio for fully offline forge:

tap config set ai.baseUrl http://localhost:11434/v1
tap config set ai.key ollama
tap config set ai.model llama3.1
tap capture https://arxiv.org/list/cs.AI/recent arxiv/recent --intent "recent papers"  # 0 bytes leave your machine

How It Works

                        ┌─ Chrome extension  (your real browser sessions)
You → AI → Taprun ──────┤
     capture            └─ Playwright        (headless, server, CI/CD)

1. You describe what you want (URL × natural-language intent)
2. AI compiles it into a .plan.json program — bare JSON, 11-op closed vocabulary, version-controlled
3. Taprun runs the program on either runtime — forever, at $0

Every successful compilation makes the next one faster. 70+ community taps mean your agent already knows the common patterns.

Community Skills

tap-skills — 70+ taps, open source.

Category	Examples
Trending	GitHub, Hacker News, Reddit, Product Hunt, Bilibili, Zhihu, Weibo, Xiaohongshu
Search	arXiv, Reddit, X, Zhihu, Weibo, Xiaohongshu, Bilibili, Medium
Read	Zhihu threads, Bilibili videos, Xiaohongshu notes, WeRead books
Write	X posts, Xiaohongshu notes, Zhihu articles, Dev.to, LinkedIn
Monitor	Price tracking, stock data, competitor analysis

tap verify <site>/<name>   # Snapshot equivalence — catches silent failures before your data goes stale
tap list                   # See everything available
tap show <site>/<name>     # Print the saved tap's plan as JSON

Local-first by architecture

Taprun runs in your browser, not someone else's cloud. The Chrome extension reuses your live login sessions; cookies, auth tokens, and credentials never leave your machine. This is a structural choice, not a marketing claim:

Concern	Cloud-first browser SDKs	Taprun (local-first)
Where do logged-in cookies live?	On the cloud vendor's servers	Only in your local browser
What does the AI see?	The full session + your data	Only the page DOM during forge time
Compliance with noindex / robots.txt / TOS	Vendor signs ToS for you	Your account, your terms
Internal / intranet sites	Need VPN tunneling	Just open the page
Decommission risk	Vendor goes down → your scrapers stop	Local code keeps running

Layer	Protection
Sandbox	Programs run with zero permissions — no file, network, or system access
Static Analysis	CI blocks dangerous patterns before they reach users
Local-only	Your data, sessions, and API keys never leave your machine — architecturally

See SECURITY.md for the full threat model.

Contributing

The easiest way to contribute: forge a new tap. One .plan.json file is all it takes.

See CONTRIBUTING.md for details.

Roadmap

• 70+ community taps across 70+ sites
• 2 runtimes — Chrome extension + Playwright (headless / CI)
• Unix pipes — tap A | tap B
• Watch mode — monitor changes over time
• Verify — tap verify snapshot-equivalence check with a 4-arm drift verdict (equivalent / drifted / first_snapshot / unreachable)
• Single-command MCP server — tap mcp stdio (or tap mcp http) for any MCP host
• Android runtime
• iOS runtime
• Concurrency control — deterministic coordination for M agents operating shared accounts in parallel

Support

• GitHub Discussions — Q&A, ideas, show & tell
• [email protected] — licensing, private feedback, consulting
• Issues — bug reports

License

Chrome Extension & docs: MIT. Community skills: MIT.

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