mcp-audit

Static security + correctness audit for MCP server repos.

pip install mcp-audit
mcp-audit                     # scan the current directory
mcp-audit /path/to/repo       # scan a specific repo
mcp-audit --json              # machine-readable output
mcp-audit --check fastmcp_wrapper_layer  # one check only
mcp-audit --list-checks       # list available checks

Exit codes: 0 clean, 1 at least one finding, 2 usage error.

What it checks

More checks are landing — hard-coded secrets, write-API tools missing a FORBIDDEN_NAMES-style guardrail, read-only-by-default violations (e.g. SQL read-only enforced by keyword prefix rather than a real read-only connection), path traversal in filesystem-touching servers.

Output format

$ mcp-audit examples/bad/
[HIGH  ] starlette_badhost @ uv.lock
           uv lockfile pins starlette==0.36.3 — vulnerable to BadHost (CVE-2026-48710). Patched in 1.0.1.
           -> Upgrade Starlette to >=1.0.1 (the BadHost patch). If FastAPI pulls Starlette transitively, pin it explicitly. ...

[HIGH  ] fastmcp_wrapper_layer @ server.py:18
           tool 'fetch_url' (def) calls asyncio.run() inside its body. FastMCP invokes tools inside an already-running event loop, and asyncio.run() raises RuntimeError when nested. This will fail at the first real MCP protocol call even if every unit test passes.
           -> Convert the tool to `async def` and replace `asyncio.run(...)` with `await`. ...

mcp-audit: 2 finding(s) — 2 high

--json emits one object: {"root": "...", "finding_count": N, "findings": [...]}. Each finding has check, severity, path, line, message, remediation.

What this is not

• It is not a runtime sandbox. Static analysis only.
• It does not install your venv to introspect it. It reads what's declared (manifests + lockfiles + source).
• It will not detect every vulnerability — only the classes its checks know about. Treat zero findings as "no known issues from this tool," not as a clean bill.

Background

• BadHost write-up: https://mcpdone.com/blog/badhost-mcp-servers
• FastMCP wrapper-layer bug write-up: https://mcpdone.com/blog/fastmcp-wrapper-layer-bug

Development

git clone https://github.com/Alienbushman/mcpdone-samples
cd mcpdone-samples/mcp-audit
pip install -e ".[dev]"
pytest
python smoke_test.py

To add a check: drop src/mcp_audit/checks/<name>.py exposing a module-level CHECK_ID and a check(root: Path) -> list[Finding] callable. Register it in src/mcp_audit/checks/__init__.py. Add fixtures + tests under tests/.

License

MIT.