mcp-server-review
Security review of MCP (Model Context Protocol) server implementations and configurations. Use when auditing MCP server source code, evaluating third-party MCP servers before installation, or reviewing Claude Code MCP integrations for overpermissioning, injection risks, and data exposure.
- Installs
- 181
- Last 24h
- —
- Trending rank
- —
- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/owasp/secure-agent-playbook --skill mcp-server-review- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads mcp-server-review automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
MCP Server Security Review
Audit an MCP server by following the full procedure in plays/mcp-server-review.md.
Steps
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Transport & Authentication — Check transport type (stdio vs HTTP/SSE), authentication on network transports, TLS enforcement, CORS policy, origin validation.
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Tool Permission Audit — For each exposed tool: document what it claims to do vs what it actually does (read source). Classify as READ-ONLY, MUTATION, DESTRUCTIVE, NETWORK, or CREDENTIAL-ACCESS. Flag tools with broader capabilities than descriptions suggest, free-form inputs, or credential access.
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Input Validation & Injection — For each tool parameter: check for command injection (shell interpolation), path traversal (../ in file paths), SQL injection (unparameterized queries), SSRF (user-supplied URLs hitting internal services), and template injection.
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Data Exposure — Assess MCP resources for secrets/PII leakage, tool outputs for excessive data, error messages for internal paths/stack traces, and logging for sensitive data capture.
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Scope & Sandboxing — Check file system restrictions, network scope (can it reach cloud metadata 169.254.169.254?), process permissions, resource limits, and dependency surface.
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Supply Chain — Verify source trustworthiness, run SCA on dependencies, check for lockfiles and reproducible builds, assess update mechanism.
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Client Configuration — Review MCP client config for absolute/specific server paths, minimized env var passthrough, and command injection safety in args.
Output
Server overview, tool risk matrix, findings using templates/finding.md, and specific configuration recommendations.
OWASP References
- LLM01: Prompt Injection (via tool descriptions and outputs)
- LLM02: Sensitive Information Disclosure
- LLM05: Improper Output Handling
- LLM06: Excessive Agency (overpermissioned tools)
- A01: Broken Access Control
- A03: Injection
FAQ
What does the mcp-server-review skill do?
Security review of MCP (Model Context Protocol) server implementations and configurations. Use when auditing MCP server source code, evaluating third-party MCP servers before installation, or reviewing Claude Code MCP integrations for overpermissioning, injection risks, and data exposure.
How do I install mcp-server-review?
Run npx skills add https://github.com/owasp/secure-agent-playbook --skill mcp-server-review in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/mcp-server-review/ (personal) or .claude/skills/mcp-server-review/ (project).
Which AI agents can use mcp-server-review?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is mcp-server-review safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains mcp-server-review?
It is published by owasp in owasp/secure-agent-playbook. It has 181 recorded installs.
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