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Claude Server

The Claude MCP bridge wraps the claude -p CLI, exposing it as an MCP server with three tools: review, ask, and code_review.

Tools​

review​

Send code, plans, or diffs for structured review. Returns a JSON object with a verdict, issues, and suggestions.

Tool: review
Input:
  content: string (required, max 500KB)
  context: string (optional)
Output:
  { verdict: "APPROVED" | "NEEDS_REVISION", issues: [...], suggestions: [...] }

The review tool uses Claude's --json-schema flag to constrain output to a predictable structure. Each issue includes a severity (critical, major, minor), description, and recommendation.

ask​

Ask Claude a freeform question about code. Useful for exploration, analysis, and understanding.

Tool: ask
Input:
  question: string (required, max 500KB)
  cwd: string (optional) -- working directory for file access
Output:
  string (freeform text response)

The cwd parameter lets Claude read files in a specific directory. This is validated against CLAUDE_ALLOWED_CWD_ROOTS for security.

code_review​

Specialized tool for reviewing git diffs.

Tool: code_review
Input:
  diff: string (required, max 500KB)
  context: string (optional)
Output:
  { verdict: "APPROVED" | "NEEDS_REVISION", issues: [...], suggestions: [...] }

How It Works​

  1. Receives an MCP tool call
  2. Constructs a prompt with the input content
  3. Spawns claude -p as a subprocess with:
    • --json-schema for structured output (review/code_review)
    • --allowedTools restricting to read-only tools
    • --permission-mode dontAsk for non-interactive operation
  4. Captures stdout and parses the JSON result
  5. Returns the structured response via MCP

Security​

  • Read-only tools: By default, Claude can only use Read, Grep, Glob, and LS
  • Working directory validation: The cwd parameter is checked against allowed roots
  • Input size limit: 500KB max per request
  • Output size limit: 10MB max response
  • Process timeout: 5 minutes default (configurable)

Configuration​

See Environment Variables for all options.

Key variables:

CLAUDE_REVIEW_MODEL=opus              # Model to use
CLAUDE_REVIEW_TIMEOUT_MS=300000       # Timeout in ms
CLAUDE_REVIEW_ALLOWED_TOOLS=Read,Grep,Glob,LS  # Tool allowlist
CLAUDE_MCP_HTTP_PORT=8940             # HTTP proxy port