Open-source mcp-audit scans MCP servers for tool poisoning before you install
Itz_hany · reddit · 2026-11-04
A Redditor released mcp-audit, an open-source tool that checks MCP servers for security risks before you install them. Key threat: tool descriptions go straight into model context — a "calculator" can secretly instruct the model to read /.cursor/mcp.json and exfiltrate it while staying silent.
- Accepts a server folder, GitHub URL, or running stdio server.
- Detects: tool poisoning (hidden instructions, credential paths, invisible Unicode, base64), over-broad tools (shell/file/URL access with no allow-list), hard-coded secrets, unsafe execution (eval, shell=True), missing auth on HTTP/SSE, and rug-pull risk (runtime-fetched descriptions).
- Findings include file, line, and fix; SARIF output plus a GitHub Action for code scanning; pure Python, zero dependencies.
- Tested on 5 public servers (official reference servers, github-mcp-server, DesktopCommander): no critical/high, 2 of 39 findings were false positives.
- Honest caveat: pattern-based, so a clean result isn't proof of safety; author requests feedback on missed patterns.
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