MCP Code Review

MCP + LLM Code Review (limps)

Purpose

Perform a security-focused, test-minded code review with emphasis on MCP servers, LLM safety, and performance risks in this repository.

Scope

Use $ARGUMENTS as the scope (paths, diff range, PR number, or component name). If no scope is provided, review the current git diff.

Workflow

1. Establish context
   • Read CLAUDE.md and relevant package docs.
   • Identify the target package (packages/limps or packages/limps-headless).
2. Threat intel + dependency hygiene
   • Search authoritative sources for new MCP/LLM or supply-chain issues:
     • OWASP LLM Top 10, OWASP API Top 10, npm advisories, GitHub Security Advisories.
   • Audit npm dependencies (use repo scripts when available):
     • npm audit --workspaces --include=prod
     • npm audit --workspaces --omit=dev (if prod-only is needed)
   • Check for outdated or abandoned packages:
     • npm outdated --workspaces
   • Inspect dependency tree for suspicious packages or name lookalikes:
     • npm ls --all --workspaces
   • Verify lockfile integrity expectations:
     • Prefer npm ci for clean installs (verifies package-lock.json integrity).
3. Enumerate change surface
   • List changed files and inspect diffs before diving into code.
4. Security-first review
   • Validate input handling, path safety, and external command usage.
   • Check for secret exposure (logs, errors, telemetry).
5. MCP/LLM safety review
   • Review tool schemas, argument validation, and permission boundaries.
   • Identify prompt injection vectors and untrusted content handling.
6. Correctness and reliability
   • Look for logic errors, race conditions, and edge cases.
7. Performance and cost
   • Identify expensive operations, redundant work, or unbounded processing.
8. Tests
   • Confirm coverage for new behavior and regression risk areas.

Repo-Specific Risk Areas

Focus extra scrutiny on:

• packages/limps/src/server.ts, src/tools/*, src/resources/* (MCP tool/resource behavior)
• packages/limps/src/rlm/* and process_doc(s) tools (untrusted code execution)
• packages/limps/src/indexer.ts and src/watcher.ts (filesystem and database safety)
• packages/limps-headless/src/tools/* (external fetchers, parsing, extraction)

MCP/LLM Security Checklist

• Validate tool inputs and guard file paths against traversal.
• Avoid executing untrusted code or shell commands without sandboxing.
• Ensure user-controlled content never becomes tool arguments without sanitization.
• Check for prompt injection via markdown, frontmatter, or external content.
• Confirm tools/resources do not leak secrets or local paths.
• Verify allowed-tools / permissions are least-privilege.
• Verify dependency integrity to reduce supply-chain risk:
  • Prefer npm ci and check lockfile integrity hashes.
  • Flag suspicious name lookalikes or unexpected transitive packages.

Output Format

Follow the repo review style:

• Findings first, ordered by severity.
• Include file references and concrete evidence.
• If no issues, say so explicitly and list residual risks or testing gaps.

Use this structure:

## Findings
- 🔴 Critical: ...
- 🟠 High: ...
- 🟡 Medium: ...
- 🟢 Low: ...

## Questions / Assumptions
- ...

## Tests
- Suggested: ...

Graph & Multi-Operation Tool Patterns

When reviewing MCP tools, check:

• Unified tool pattern: Multi-operation tools (like graph with subcommands: health, search, trace, check, suggest, reindex) should validate the operation parameter and dispatch correctly.
• Graph DB error handling: Tools that use better-sqlite3 must handle DB open failures, missing tables, and corrupt data gracefully.
• Input validation: All MCP tool schemas should validate inputs before processing. Check for path traversal, SQL injection in FTS queries, and oversized inputs.

Notes

• Prefer ReadFile, Grep, Glob over shell tools for code inspection.
• Avoid speculative claims; cite code or call out uncertainty.

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