Model Context Protocol (MCP)

The Model Context Protocol (MCP) is an open standard that enables AI applications to securely connect to external data sources and tools. Codegen provides an MCP server that allows AI editors like Cursor to access Codegen’s powerful codemod generation and SDK capabilities directly within your development workflow.

What is MCP?

MCP acts as a bridge between AI assistants and external tools, allowing them to:

Access external data sources and APIs
Execute tools and commands safely
Provide rich context to improve AI responses
Maintain security through standardized protocols

With Codegen’s MCP integration, your AI editor can:

Generate codemods using the Codegen SDK
Access Codegen documentation and examples
Get expert guidance on Codegen best practices
Streamline your code transformation workflows

Prerequisites

Before setting up the MCP server, ensure you have:

Codegen CLI installed: Install via pip or your preferred package manager
```
pip install codegen
```
Authentication: Log in to your Codegen account
```
codegen login
```
AI Editor with MCP support: Currently supported editors include:
- Cursor (recommended)
- Claude Desktop
- Cline (VS Code extension)

Quick Start

1. Start the MCP Server

The easiest way to start the Codegen MCP server is using the built-in CLI command:

codegen mcp

This starts the server with default settings (stdio transport). For additional options:

# Start with verbose logging
codegen mcp --verbose

# Start with HTTP transport on a specific port
codegen mcp --transport http --port 8080

# View all available options
codegen mcp --help

2. Configure Your AI Editor

The configuration depends on your AI editor. See the sections below for specific setup instructions.

Cursor Configuration

Cursor provides the most seamless MCP integration experience. Follow these steps:

Method 1: Using Cursor Settings (Recommended)

Open Cursor Settings
- Press Cmd/Ctrl + , to open settings
- Navigate to Features → MCP Servers
Add New MCP Server
- Click “Add New MCP Server”
- Fill in the following details:
```
Name: codegen-mcp
Type: Command
Command: codegen mcp
```
Save and Restart
- Click “Save”
- Restart Cursor to activate the MCP server

Method 2: Manual Configuration File

If you prefer manual configuration, you can edit Cursor’s MCP configuration file directly:

Locate the configuration file:
- macOS: ~/Library/Application Support/Cursor/User/mcp_servers.json
- Windows: %APPDATA%\Cursor\User\mcp_servers.json
- Linux: ~/.config/Cursor/User/mcp_servers.json

Add the Codegen MCP server:

{
  "mcpServers": {
    "codegen-mcp": {
      "command": "codegen",
      "args": ["mcp"]
    }
  }
}

Restart Cursor to load the new configuration.

Verification

To verify the MCP server is working in Cursor:

Open a new chat in Cursor
Look for “Available Tools” in the chat interface
You should see Codegen MCP tools listed, such as:
- generate_codemod
- ask_codegen_sdk
- improve_codemod

Alternative Editors

Claude Desktop

For Claude Desktop, add this configuration to your claude_desktop_config.json:

{
  "mcpServers": {
    "codegen-mcp": {
      "command": "codegen",
      "args": ["mcp"]
    }
  }
}

Configuration file locations:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

Cline (VS Code Extension)

For the Cline VS Code extension, add this to your cline_mcp_settings.json:

{
  "mcpServers": {
    "codegen-mcp": {
      "command": "codegen",
      "args": ["mcp"]
    }
  }
}

Available Tools

Once configured, the Codegen MCP server provides these tools to your AI editor:

`generate_codemod`

Generate a new codemod for a specific task and codebase. Parameters:

title: The title of the codemod (hyphenated format)
task: Description of what the codemod should accomplish
codebase_path: Absolute path to your codebase directory

Example usage in chat:

Generate a codemod called "add-logging" that adds console.log statements to all functions in my React components at /path/to/my/project

`ask_codegen_sdk`

Get expert guidance on any aspect of the Codegen SDK. Parameters:

query: Your question about the Codegen SDK

Example usage in chat:

How do I use the Codebase class to analyze TypeScript files?

`improve_codemod`

Improve an existing codemod based on feedback and concerns. Parameters:

codemod_source: The source code of the codemod to improve
task: The original task description
concerns: List of issues discovered with the current codemod
context: Additional context and related files
language: Programming language (e.g., PYTHON, TYPESCRIPT)

Authentication

The MCP server uses your existing Codegen authentication. Ensure you’re logged in:

# Check current authentication status
codegen profile

# Log in if needed
codegen login

If you encounter authentication issues:

Verify your login status: codegen profile
Re-authenticate if needed: codegen logout && codegen login
Check your API token: Ensure your token hasn’t expired

Troubleshooting

Common Issues

MCP Server Not Starting

Verify Codegen is properly installed: codegen --version
Check authentication: codegen profile
Try running with verbose logging: codegen mcp --verbose

Tools Not Appearing in Editor

Restart your AI editor after configuration changes
Check the MCP server configuration syntax
Verify the codegen command is in your system PATH

Permission Errors

Ensure the codegen command is executable
Check file permissions on configuration files
Try running the editor with appropriate permissions

Path Resolution Issues

Use absolute paths in configuration when possible
Verify the codegen command location: which codegen
Consider using the full path to the codegen executable

Advanced Configuration

Custom Server Path If you need to specify a custom path to the Codegen installation:

{
  "mcpServers": {
    "codegen-mcp": {
      "command": "/path/to/your/codegen",
      "args": ["mcp"]
    }
  }
}

Environment Variables You can set environment variables for the MCP server:

{
  "mcpServers": {
    "codegen-mcp": {
      "command": "codegen",
      "args": ["mcp", "--verbose"],
      "env": {
        "CODEGEN_API_URL": "https://api.codegen.com",
        "CODEGEN_MCP_VERBOSE": "1"
      }
    }
  }
}

HTTP Transport For remote or multi-user setups, you can use HTTP transport:

# Start server with HTTP transport
codegen mcp --transport http --port 8080

Then configure your editor to connect to the HTTP endpoint instead of using the command interface.

Best Practices

Keep Codegen Updated: Regularly update to get the latest MCP features
```
codegen update
```
Use Descriptive Codemod Names: Use clear, hyphenated names for generated codemods
```
Good: "add-error-handling", "migrate-to-hooks"
Avoid: "fix", "update", "change"
```

Provide Clear Task Descriptions: Be specific about what you want the codemod to accomplish

Good: "Add try-catch blocks around all async function calls in React components"
Avoid: "Add error handling"

Test Generated Codemods: Always review and test generated codemods before applying them to production code
Use Version Control: Commit your code before running codemods to easily revert if needed

Examples

Example 1: Generate a React Hook Migration Codemod

In your AI editor chat:

Use the generate_codemod tool to create a codemod called "migrate-class-to-hooks" that converts React class components to functional components with hooks. The codebase is located at /Users/myname/projects/my-react-app

Example 2: Get SDK Help

Use ask_codegen_sdk to explain how to use the FileAnalyzer class to detect unused imports in Python files

Example 3: Improve an Existing Codemod

I have a codemod that's not working correctly. Use improve_codemod to fix it. The codemod source is: [paste your codemod code]. The task was to add TypeScript types to function parameters, but it's missing some edge cases for arrow functions and async functions.

Support

If you encounter issues with the MCP integration:

Check the documentation: Review this guide and the official MCP documentation
Enable verbose logging: Use codegen mcp --verbose for detailed error information
Community support: Join our Discord community for help
Report bugs: Create an issue on our GitHub repository

What’s Next?

With Codegen MCP integration set up, you can:

Generate codemods directly from your AI editor
Get instant help with Codegen SDK questions
Streamline your code transformation workflows
Iterate quickly on codemod improvements

Explore our SDK documentation to learn more about Codegen’s capabilities, or check out our examples repository for inspiration.

Overview

Capabilities

Integrations

Sandboxes

Settings

Model Context Protocol (MCP)

Model Context Protocol (MCP)

What is MCP?

Prerequisites

Quick Start

1. Start the MCP Server

2. Configure Your AI Editor

Cursor Configuration

Method 1: Using Cursor Settings (Recommended)

Method 2: Manual Configuration File

Verification

Alternative Editors

Claude Desktop

Cline (VS Code Extension)

Available Tools

`generate_codemod`

`ask_codegen_sdk`

`improve_codemod`

Authentication

Troubleshooting

Common Issues

Advanced Configuration

Best Practices

Examples

Example 1: Generate a React Hook Migration Codemod

Example 2: Get SDK Help

Example 3: Improve an Existing Codemod

Support

What’s Next?

Overview

Capabilities

Integrations

Sandboxes

Settings

​Model Context Protocol (MCP)

​What is MCP?

​Prerequisites

​Quick Start

​1. Start the MCP Server

​2. Configure Your AI Editor

​Cursor Configuration

​Method 1: Using Cursor Settings (Recommended)

​Method 2: Manual Configuration File

​Verification

​Alternative Editors

​Claude Desktop

​Cline (VS Code Extension)

​Available Tools

​generate_codemod

​ask_codegen_sdk

​improve_codemod

​Authentication

​Troubleshooting

​Common Issues

​Advanced Configuration

​Best Practices

​Examples

​Example 1: Generate a React Hook Migration Codemod

​Example 2: Get SDK Help

​Example 3: Improve an Existing Codemod

​Support

​What’s Next?

Model Context Protocol (MCP)

What is MCP?

Prerequisites

Quick Start

1. Start the MCP Server

2. Configure Your AI Editor

Cursor Configuration

Method 1: Using Cursor Settings (Recommended)

Method 2: Manual Configuration File

Verification

Alternative Editors

Claude Desktop

Cline (VS Code Extension)

Available Tools

`generate_codemod`

`ask_codegen_sdk`

`improve_codemod`

Authentication

Troubleshooting

Common Issues

Advanced Configuration

Best Practices

Examples

Example 1: Generate a React Hook Migration Codemod

Example 2: Get SDK Help

Example 3: Improve an Existing Codemod

Support

What’s Next?