CodePeel MCP Server

A Model Context Protocol (MCP) server for AI-powered code review. Enables LLMs to review code diffs, generate fixes, and ask code questions — using the same engine that runs on 527+ GitHub PRs.

Features

• Code Review: Review diffs for bugs, security issues, and best practice violations
• Auto-Fix: Generate fixes for specific issues with code snippets and explanations
• Ask CodePeel: Query code patterns, architecture decisions, and improvement suggestions
• Check Credits: Monitor your review quota and usage (free — does not consume a review)
• Reusable Prompts: Pre-built workflows for pre-commit review, security audit, and explain-and-fix

Quick Start

Installation (NPX - Recommended)

No installation required! Run directly with npx:

npx -y @codepeelai/mcp-server

Prerequisites

1. CodePeel API Token: Create at codepeel.com → Settings → API Tokens
   • Token starts with cpk_ and does not expire until revoked
2. Node.js 18+: Required for running the server

Configuration

Claude Desktop Configuration

Configuration file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%/Claude/claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Add the CodePeel MCP server:

{
  "mcpServers": {
    "codepeel": {
      "command": "npx",
      "args": ["-y", "@codepeelai/mcp-server"],
      "env": {
        "CODEPEEL_TOKEN": "cpk_your_token_here"
      }
    }
  }
}

Restart Claude Desktop after saving.

Claude Code Configuration

Create or edit .claude/settings.json in your project:

{
  "mcpServers": {
    "codepeel": {
      "command": "npx",
      "args": ["-y", "@codepeelai/mcp-server"],
      "env": {
        "CODEPEEL_TOKEN": "cpk_your_token_here"
      }
    }
  }
}

Pro tip: Use environment variables instead of hardcoding the token:

{
  "mcpServers": {
    "codepeel": {
      "command": "npx",
      "args": ["-y", "@codepeelai/mcp-server"],
      "env": {
        "CODEPEEL_TOKEN": "${CODEPEEL_TOKEN}"
      }
    }
  }
}

Then set the CODEPEEL_TOKEN environment variable in your shell before starting Claude Code.

VS Code / Cursor / Cline / Roo

Add an MCP server with:

• Command: npx
• Args: -y @codepeelai/mcp-server
• Env: CODEPEEL_TOKEN=cpk_your_token_here

Usage

Automated Workflow Prompts

Use built-in MCP prompts for complete review workflows:

review-staged-changes — Pre-commit review

Review my staged changes before I commit them.
1. Run `git diff --cached` to get the staged diff
2. Pass the diff to the `review_code` tool
3. Report all findings and suggest fixes for any issues

security-audit — Security-focused review

Perform a security-focused code review.
1. Get the current diff with `git diff`
2. Pass it to the `review_code` tool
3. Prioritize: injection vulnerabilities, hardcoded secrets, auth flaws, insecure data handling
4. For critical/high findings, use `fix_code` to generate concrete fixes

explain-and-fix — Full review cycle

Review code, explain each finding in detail, and generate fixes for all issues found.
1. Run `git diff` to get changes
2. Pass to `review_code`
3. For each finding: explain the issue, describe impact, use `fix_code`, apply the fix
4. Summarize all changes made

Manual Tool Usage

1. review_code

Review a diff for bugs, security issues, and best practice violations.

{
  "diff": "--- a/src/auth.ts\n+++ b/src/auth.ts\n@@ -10,7 +10,7 @@\n-  const token = req.headers.authorization;\n+  const token = req.headers.authorization?.split(' ')[1];",
  "repo": "my-app"
}

2. fix_code

Generate a fix for a specific code issue.

{
  "file": "src/auth.ts",
  "issue": "Token extraction from Authorization header is unsafe — crashes if header is missing",
  "problemCode": "const token = req.headers.authorization;",
  "line": 12,
  "severity": "high"
}

3. ask_codepeel

Ask a question about code patterns, architecture, or improvements.

{
  "question": "Is this JWT validation approach secure enough for production?",
  "diff": "--- a/src/middleware.ts\n+++ b/src/middleware.ts\n..."
}

4. check_credits

Check your account balance, plan tier, and usage.

{}

Development Installation

For development or local customization:

git clone https://github.com/hexivine/codepeel.git
cd codepeel/codepeel-mcp
npm install
npm run build

Development Commands

# Build TypeScript
npm run build

# Run the server in dev mode
npm run dev

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | CODEPEEL_TOKEN | Yes | Your API token from Settings (starts with cpk_) |

Create a .env file (optional, loaded automatically):

CODEPEEL_TOKEN=cpk_your_token_here

Troubleshooting

Common Issues

Server not loading (NPX):

• Verify Node.js 18+ is installed: node --version
• Test npx execution manually: npx -y @codepeelai/mcp-server
• Check your internet connection (npx downloads the latest version)

"CODEPEEL_TOKEN not set":

• Set the CODEPEEL_TOKEN environment variable in your MCP config (see Configuration above)

"Token expired" / "Invalid token":

• You're using a Firebase ID token instead of an API token. Create a cpk_ token in Settings → API Tokens.

"No credits remaining":

• Upgrade your plan at codepeel.com/#pricing or wait for credits to reset.

Rate limit exceeded:

• Wait the indicated time and retry. Free: 3/hour, Pro: 6/hour, Max: 12/hour.

Server starts but tools don't appear:

• Restart your AI editor after adding the MCP config.
• Verify the command is "npx" and args are ["-y", "@codepeelai/mcp-server"].

Debug Mode

Enable debug logging:

DEBUG=* npx -y @codepeelai/mcp-server

Integration Requirements

Supported AI Clients

• Claude Desktop: Full support with configuration
• Claude Code: Project-level MCP integration with built-in prompts
• VS Code / Cursor / Cline / Roo: Any MCP-compatible editor

Authentication

API tokens are created at codepeel.com → Settings → API Tokens. Tokens start with cpk_ and do not expire until revoked.

Architecture

• TypeScript: Fully typed implementation with Zod validation
• MCP SDK: Built on the official Model Context Protocol SDK
• Modular Design: Each tool is implemented in its own module
• MCP Prompts: Automated workflows available as slash commands

API Rate Limits

The server respects CodePeel's API rate limits:

• Free: 3 reviews/hour
• Pro: 6 reviews/hour
• Max: 12 reviews/hour

Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature-name
3. Make your changes and add tests
4. Run the build: npm run build
5. Submit a pull request

License

MIT

Support

• Issues: GitHub Issues
• Documentation: codepeel.com/docs/mcp