🛡️ MCPatrol

Lighthouse for MCP servers. Point it at any HTTP MCP endpoint and get back a security, cost, and quality report card in 30 seconds.

Why this exists

MCP servers are exploding in production — every major AI lab now supports the protocol, and they're being deployed faster than they're being audited. Public reporting (RSAC 2026, Perplexity CTO at Ask 2026) flagged real problems:

• Tool descriptions burning 40-50% of context windows before agents do any work
• Prompt-injection through tool descriptions ("rugpull" attacks)
• Auth handled inconsistently — many servers ship with bearer-token gaps
• Error responses leaking stack traces, file paths, and env vars

MCPatrol is a free, open-source CLI that tests for all of these in one command. No infrastructure, no signup. Audit a server, get an HTML report card, fix what matters.

Install

pip install mcpatrol

Use

# Audit a remote MCP server (HTTP or SSE)
mcpatrol https://my-mcp-server.com/sse

# With auth header
mcpatrol https://my-mcp-server.com/sse --auth-header "Bearer xyz123"

# Skip the slow tests (no latency loop, no Claude scoring)
mcpatrol https://my-mcp-server.com/sse --quick --no-quality

# Generate a demo report (no network, no API calls)
mcpatrol --demo

The output is a self-contained mcpatrol-report.html that opens in your browser. Share it, screenshot it, commit it to your repo.

What it checks

Every finding includes a CWE-style category, severity, and concrete remediation.

Honest scope

MCPatrol is a starting point, not a comprehensive pentest. It catches the common, public attack classes documented in the early-2026 MCP security research. It will not catch sophisticated zero-days, server-side bugs requiring authentication you don't have, or anything that requires source-code access.

Treat it like Lighthouse for the web — a fast first pass that flags the obvious problems, not a SOC 2 audit.

Quality scoring needs your API key

The optional --with-quality mode uses Claude to score tool descriptions. It uses your Anthropic API key:

export ANTHROPIC_API_KEY=sk-ant-...
mcpatrol https://my-mcp-server.com/sse

Cost: ~$0.001 per tool. Auditing a 40-tool server runs about 4 cents. Skip with --no-quality if you'd rather pay zero.

MCPatrol never sees, transmits, or stores your API key — it goes from your env directly to Anthropic.

What's coming

• stdio (local) MCP servers via --launch "command args"
• More security probes: SSE state-confusion, race conditions, auth flow tests
• CI mode: exit non-zero if grade drops below threshold
• JSON Schema spec for the findings format (so you can build dashboards on it)
• Markdown summary output (for PR comments)

Contributing

This is a brand-new project. Open issues, suggest probes, or PR new ones — every probe should map to a real, public attack class with a citation in the docstring.

License

MIT. Use it, fork it, ship it.

Built with care, in public.