tapsite

The MCP server for web intelligence extraction. 43 tools that give AI agents the ability to understand websites — not just drive a browser, but extract structured intelligence about design systems, accessibility, performance, content, and more.

Other MCP browser tools let agents click buttons. tapsite lets agents extract a complete color palette, audit WCAG contrast ratios, diff two sites' design tokens, or track accessibility regressions over time — all as structured JSON that agents can reason about.

Works with Claude, Cursor, Windsurf, and any MCP-compatible AI agent. LangChain/LangGraph integration coming soon.

View the full docs site →

Installation

# Quick start (no install required)
npx -y tapsite

# Or install globally
npm install -g tapsite
npx playwright install chromium
npx playwright install-deps chromium

Add to your AI agent's MCP config:

{
  "mcpServers": {
    "tapsite": {
      "command": "npx",
      "args": ["-y", "tapsite"]
    }
  }
}

First run: Playwright will install Chromium automatically if not already present (~150MB one-time download).

Also available on the MCP Registry and Glama.

What tapsite does

Extract design systems — colors, fonts, spacing scales, breakpoints, components, shadows, icons, CSS variables, and contrast ratios from any website. Output as structured JSON or W3C design tokens.

Audit quality — accessibility scoring with WCAG contrast analysis, performance timing (Core Web Vitals), tech stack detection, dark mode support, and animation inventory.

Compare and track — diff two sites side by side, or track a single site over time with snapshot-based temporal diffs. Regressions and improvements are flagged automatically.

Work behind login walls — persistent browser sessions with full MFA support. Log in once manually, then extract across tool calls without re-authenticating. Credentials never enter the chat.

Showcase

Click any image to see the full interactive page:

Design System Extraction	Deep Intelligence
Live-extracted colors, fonts, perf, breakpoints, and animations from Stripe, Linear, and Vercel	Accessibility audits, content extraction, form analysis, asset inventory, component detection

Tools (43)

Session

Content Extraction

Design Tokens

Visual Assets

Layout Intelligence

Network Intelligence

Multi-page

Advanced

Export

Workflows (Presets)

LangChain / LangGraph integration (coming soon)

Native LangChain and LangGraph integration is on the roadmap. When released, it will provide a dedicated Python wrapper with tool subsets and managed session lifecycle.

Security

Prompt injection defense

When extracting content from untrusted web pages, tapsite applies two layers of protection:

1. Hidden element filtering — Extractors skip elements with display:none, visibility:hidden, opacity:0, zero-size, and clip-hidden styling. This prevents invisible text (a common prompt injection vector) from entering extraction results.

2. Output sanitization — All text returned to the LLM is scanned for prompt injection patterns: instruction overrides, role hijacking, exfiltration attempts, and tool manipulation. Matches are flagged inline as [INJECTION_DETECTED] rather than silently dropped.

Credential safety

Never pass credentials through the chat. Use tapsite_login_manual to open a headed browser, log in manually (including MFA), then tapsite_login_check to confirm. Credentials never touch the AI provider's servers or local transcripts.

Docker

tapsite ships a Dockerfile and docker-compose.yml for headless-only use — CI pipelines, server deployments, or anywhere you don't want a local Node.js install.

docker build -t tapsite .
docker compose up

tapsite_login_manual is not available in Docker (it requires a display). To use authenticated sessions in Docker, log in locally first, then mount the profiles/ directory into the container:

volumes:
  - ./output:/app/output
  - ./profiles:/app/profiles

Security note: profiles/ contains live session cookies. Don't commit it to version control (it's already in .gitignore).

Development setup

git clone https://github.com/mgriffen/tapsite
cd tapsite
npm install
npx playwright install chromium
npx playwright install-deps chromium

MCP config pointing to local source:

{
  "mcpServers": {
    "tapsite": {
      "command": "node",
      "args": ["/absolute/path/to/tapsite/src/server.js"]
    }
  }
}

Project structure

src/
  server.js        — MCP server entry point
  browser.js       — shared Chromium context (ensureBrowser, closeBrowser)
  helpers.js       — shared helpers (navigateIfNeeded, summarizeResult, indexPage)
  sanitizer.js     — prompt injection detection
  diff.js          — per-extractor diff logic and extractor name/args mapping
  snapshots.js     — temporal snapshot I/O (saveSnapshot, loadLatestSnapshot)
  extractors.js    — browser-context extraction functions (page.evaluate())
  exporter.js      — file export: JSON, Markdown, HTML, CSV
  inspector.js     — DOM extraction for inspect tools
  cli.js           — standalone CLI (login, inspect, session)
  config.js        — paths and defaults
  tools/
    session.js     — login, inspect, screenshot, interact, scroll, run_js, close
    extraction.js  — all extract_* tools
    network.js     — capture_network, extract_api_schema, extract_stack
    multipage.js   — crawl, diff_pages
    export.js      — export, export_design_report
    workflows.js   — teardown, audit, harvest, designsystem
profiles/          — browser state / session cookies (gitignored)
output/            — export results + snapshots (gitignored)

Output formats

• output/run-{timestamp}/ — tapsite_export: JSON, Markdown, HTML, screenshots, CSV tables
• output/design-report-{timestamp}/ — tapsite_export_design_report: report.html, design-tokens.json, design-tokens.css
• output/snapshots/{domain}/ — tapsite_diff_pages temporal snapshots

License

MIT