Tap

io.github.LeonTing1010Published by GitHub account LeonTing1010v0.30.1Updated Nov 7, 2026

Browser MCP for logged-in tasks. Uses your Chrome — credentials stay local. Zero-token replay.

VerifiedStreamable HTTPWeb executableWeb Search & ScrapingBrowser AutomationDeveloper Tools

Overview

AI-generated overview

Tap lets an assistant capture a website action once and replay it deterministically in your own logged-in Chrome, at zero LLM tokens per run.

What you can do
  • Capture a tap from a URL plus a natural-language intent, compiling it into a saved flow program
  • Verify a saved tap with a read-only check that reports whether the page still matches or has drifted
  • Resolve uncertain intent while authoring a tap
  • Run a saved tap to replay the recorded action and return its result
  • On the hosted edge demo, run only the tab-free demo taps referenced as demo/
When to use it
Useful when an assistant must reach pages behind logins, OTP walls or human-gesture gates that clean APIs and cloud agents cannot touch, and when you want repeatable, token-free replays instead of re-running a live model on every execution. The hosted demo is enough to try read-only open-API taps without installing anything.
Requirements
Either the remote endpoint at mcp.taprun.dev (read-only demo taps only) or a local install via the npm package @taprun/cli or the PyPI package taprun over stdio. Logged-in sites need the Chrome extension and a one-time Add to Chrome click; public pages can use a Playwright runtime with --no-extension. Forging taps with AI may need a model provider key or a local OpenAI-compatible endpoint. No authentication or environment variables are declared for the MCP server itself.
Before you install
The hosted edge demo is read-only and limited to demo taps; write actions and logged-in sessions require the local install. Taps can perform write actions such as publishing posts, so review a captured flow before replaying it. The Chrome extension reuses your live login sessions, so anything a tap does runs under your own account. Forging taps with a hosted model sends page content to that provider unless you point it at a local endpoint.

Installation

In SourceWeft

  1. Open Tap in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.LeonTing1010%2Ftap/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "tap": {
      "type": "http",
      "url": "https://mcp.taprun.dev/mcp"
    }
  }
}

README

[Taprun]

Taprun

The action layer your agent drives in your own logged-in browser — for the exception-heavy, compliance-critical last 20% that clean APIs can't reach. Compiled once, replayed forever at zero LLM tokens.

Homepage  |  Blog  |  Verified Claims  |  📬 Drift Alerts  |  中文

[CI] [Release] [Stars] [License] [Chrome Web Store]

[Taprun: AI compiles a Hacker News tap once for $0.42, then replays forever at $0 per run]

Your agent's closed-loop action layer for the browser — the login-gated, exception-heavy, compliance-critical last 20% that clean APIs and cloud agents can't reach. Driven in your own Chrome, captured once, replayed forever at zero LLM tokens.

As APIs get walled off and metered, the work that survives lives behind logins, OTP walls, and human-gesture gates — the exceptions, approvals, and compliance steps a cloud agent architecturally can't touch. Taprun is the action layer for exactly that: your agent drives your real, already-logged-in Chrome, closes the loop (act → verify the effect → re-run on drift), and hands you a deterministic replay you own.

Every other browser agent re-runs a live LLM — and re-burns tokens — on every execution. Taprun's AI agent inspects the page once and emits a deterministic .flow.json program; every replay after that is pure data dispatch — same result every call, $0 in tokens, no agent in the loop. It runs in your real Chrome, so cookies and login sessions stay on your machine by architecture. tap verify catches breakage before your data goes stale.

Works with Claude Code, CodeBuddy, Cursor, Cline, Windsurf, and any MCP host — install straight from the chat window. Forge a tap from any URL on demand — no catalog needed.

Capture: AI inspects the site → compiles a .flow.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

TaprunAI Browser AgentsTraditional Scrapers
AI cost per run$0 (compile once)Tokens every runFree
AccuracyDeterministicVaries per runDeterministic
Silent failure detectionPer-tap CEL snapshot_equivalent predicate + 4-arm verdictNoneNone
Breakage diagnosticstap verify — exact diff of what changedNoneManual spot checks
Detection riskLow (real browser sessions)HighHigh
Runtimes2 (Chrome extension + Playwright)11
Code inspectable.flow.json — bare JSON, 18-op closed vocabulary, git diffBlack box / ephemeralFragile scripts
MCP nativeYes (authoring layer only — execution is zero tokens)NoNo

Get Started

1. Attach to your agent — from the chat window

Claude Code / CodeBuddy — paste two lines into the chat, nothing else:

/plugin marketplace add LeonTing1010/taprun/plugin install tap@taprun

That installs the Taprun MCP server plus the skills that teach your agent when to use it and the hook that routes walled fetches to Taprun — no terminal, no config file. (CodeBuddy wires plugin MCP servers at startup only, so fully restart it once after installing; Claude Code picks them up with /reload-plugins.)

Any other MCP host (Cursor · VS Code · Claude Desktop) — one command writes the config for you:

bash
npx -y @taprun/cli embed cursor   # or: vscode | claude-desktop | claude-code | codebuddy | qwen

The binary self-copies to ~/.tap/bin and your agent's MCP config is written. Re-check anytime with tap embed --verify.

Using a coding agent that isn't in that list? tap embed targets are data, not code: drop a row into ~/.tap/embed-targets.json and the new agent works immediately — no engine release. Each row names one of four install kinds (cc-plugin for Claude-Code-plugin hosts, cli-mcp-add for CLIs with a <cli> mcp add, ide-deeplink, desktop-bundle), e.g. [{"id":"kode","kind":"cc-plugin","display":"Kode CLI","tier":1,"cli":"kode"}]. Same doctrine as the rest of Taprun — the engine stays closed and mechanical; you extend it in local data.

Now pick your runtime — the extension is only needed to reuse your live logged-in Chrome:

  • Public pages / open APIs / CI — nothing more to install. The MCP server runs over npx; you're done. Append --no-extension for a fully in-chat Playwright runtime with its own isolated profile (no browser gesture, no click).
  • Logged-in sites (your bank / internal dashboard / Xiaohongshu / Zhihu) — just tell your agent "set up tap for logged-in sites" right in the chat. The tap-setup skill drives the whole bridge from the chat: it materializes the stable binary (from the engine npx already downloaded — no second download) and registers the native-messaging manifest, then opens the extension page. The single Add to Chrome click is the only step that isn't a chat action — it is the trust gate that lets Taprun reuse your existing login, and the in-flight call resumes automatically once it lands.
  • Claude Desktop: download tap.mcpb and double-click.
Other install paths (brew · curl · manual MCP JSON · raw binaries)
bash
brew install LeonTing1010/tap/taprun            # Homebrew (macOS / Linux)curl -fsSL https://taprun.dev/install.sh | sh   # permanent binarynpx -y @taprun/cli --version                    # zero-install (any Node host)

Manual MCP config, if you'd rather write it yourself:

json
{ "mcpServers": { "tap": { "command": "npx", "args": ["-y", "@taprun/cli", "mcp", "stdio"] } } }
PlatformDownload
macOS (Apple Silicon)tap-macos-arm64
macOS (Intel)tap-macos-x64
Linuxtap-linux-x64
Windowstap-windows-x64.exe

2. Prove it works (~2 minutes, no login)

Run the first entry of the claims ledger — the exact verification its nightly CI runs:

bash
mkdir -p ~/.tap/flows/githubcurl -fsSL https://raw.githubusercontent.com/LeonTing1010/tap-skills/main/claims/2026-07-11-github-trending-has-no-api/plan.json \  -o ~/.tap/flows/github/trending-no-api.flow.jsontap github/trending-no-api

"state": "committed" plus today's trending repos at zero tokens = your install works and the claim holds.

3. Forge your own

bash
tap capture https://news.ycombinator.com hn/front --intent "front-page stories with points"tap hn/front        # replay forever, $0

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 moviesAgent: Done. Run `tap douban/top250` anytime — $0 per run.

Optional: Drive the binary from your own code (TypeScript / Python)

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

bash
tap capture <url> hackernews/top --intent "front-page top stories"tap hackernews/top --args '{}'    # JSON-on-stdout, exit 0 on successtap verify hackernews/top         # 3-arm verdict (live / drifted / unreachable)

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 Taprun-compatible .flow.json plan out:

bash
# Existing Playwright script (47M weekly npm downloads — most likely the one you have)npm install @taprun/from-playwright @taprun/specnode -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 scratchnpx create-tap-script github/trending https://github.com/trending
AdapterSource formatCoverage
@taprun/from-playwright.ts/.js Playwright tests8 page.* APIs (goto/click/fill/type/press/waitForSelector/waitForTimeout/screenshot)
@taprun/from-puppeteer.ts/.js Puppeteer scripts7 page.* APIs + page.keyboard.press
@taprun/from-stagehand.ts/.js Stagehand scriptsHybrid: deterministic page.* mapped to plan ops; NL act/extract/observe flagged for honest verify verdicts
create-tap-script(none — scaffolder)Generates a starter .flow.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 (18-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 Taprun 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

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

Write — Operate any website

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

Watch — Monitor changes

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

Compose — Chain like Unix pipes

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

Forge — Create new automations with AI

bash
tap capture https://news.ycombinator.com hackernews/hot --intent "top stories"   # API detected — compiled without AItap 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:

bash
tap config set ai.baseUrl http://localhost:11434/v1tap config set ai.key ollamatap config set ai.model llama3.1tap 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 .flow.json program — bare JSON, 18-op closed vocabulary, version-controlled
  3. Taprun runs the program on either runtime — forever, at $0

Every successful compilation makes the next one faster. Need a tap for a new site? Your agent forges one on demand with capture — no catalog required.

Verified Claims

tap-skills is no longer a skills catalog — it's a claims ledger: dated, falsifiable claims about the live web, each vendoring its own deterministic plan, re-verified nightly by CI at zero LLM tokens. A claim that drifts flips to 🟡 publicly, the same night.

Verify the first claim yourself (~2 minutes, no login, no browser):

bash
mkdir -p ~/.tap/flows/githubcurl -fsSL https://raw.githubusercontent.com/LeonTing1010/tap-skills/main/claims/2026-07-11-github-trending-has-no-api/plan.json \  -o ~/.tap/flows/github/trending-no-api.flow.jsonnpx -y @taprun/cli github/trending-no-api

You get the exact verification the nightly CI gets — deterministic replay, same result. The 140-skill v1 catalog is preserved untouched on the v1-archive branch; pre-built catalogs only rot, so plans are forged on demand with capture instead.

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

Local-first by architecture

Zero-token replay is the headline; local-first is the guarantee underneath it. Taprun runs in your browser — the Chrome extension reuses your live login sessions, so cookies, auth tokens, and credentials never leave your machine. A structural choice, not a marketing claim:

ConcernCloud-first browser SDKsTaprun (local-first)
Where do logged-in cookies live?On the cloud vendor's serversOnly in your local browser
What does the AI see?The full session + your dataOnly the page DOM during forge time
Compliance with noindex / robots.txt / TOSVendor signs ToS for youYour account, your terms
Internal / intranet sitesNeed VPN tunnelingJust open the page
Decommission riskVendor goes down → your scrapers stopLocal code keeps running
LayerProtection
SandboxPrograms run with zero permissions — no file, network, or system access
Static AnalysisCI blocks dangerous patterns before they reach users
Local-onlyYour 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 .flow.json file is all it takes.

See CONTRIBUTING.md for details.

Roadmap

  • Community skills catalog — retired 2026-07 in favor of the claims ledger (v1 catalog archived)
  • 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

Privacy

Taprun is local-first by architecture. It drives your own browser on your own machine — credentials, cookies, and page data never leave it. The engine ships no telemetry and makes no outbound network calls except the ones your own saved taps explicitly direct (op:fetch). Saved taps, secrets, and traces live under ~/.tap/ on your machine only.

Full policy: taprun.dev/privacy.

License

Chrome Extension & docs: MIT. Claims ledger: MIT.

Star History

[Star History Chart]

Source: README.md at commit 85f6110

Tools

4

capture

Create a tap from URL × intent (local install only).

Parametersurlintent

verify

Read-only substrate check (local install only).

Parametersnamesite

mark

Resolve uncertain intent (local install only).

Takes no parameters.

run

Execute a saved tap. On this edge demo, runs the tab-free demo taps. ref = demo/<name>.

Parametersrefrequiredargs

Version history

2
  1. v0.30.1LatestNov 7, 2026
  2. v0.29.2Sep 16, 2026

Score

100% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts