bundler_mcp

A Model Context Protocol (MCP) server enabling AI agents to query information about dependencies in a Ruby project's Gemfile. Built with fast-mcp.

[](https://github.com/subelsky/bundler_mcp/actions/workflows/main.yml) [](https://badge.fury.io/rb/bundler_mcp)

Install the gem and add to the application's Gemfile by executing:

bundle add bundler_mcp --group=development

1. Generate the binstub:

bundle binstubs bundler_mcp

1. Configure your client to execute the binstub. Here are examples that work for Claude and Cursor:

{
  "mcpServers": {
    "bundler-mcp": {
      "command": "/Users/mike/my_project/bin/bundler_mcp"
    }
  }
}

{
  "mcpServers": {
    "bundler-mcp": {
      "command": "/Users/mike/my_project/bin/bundler_mcp",

      "env": {
        "BUNDLER_MCP_LOG_FILE": "/Users/mike/my_project/log/mcp.log",
        "BUNDLE_GEMFILE": "/Users/mike/my_project/subdir/Gemfile"
      }
    }
  }
}

Available on RubyDoc

The server provides two tools for AI agents:

Lists all bundled Ruby gems with their:

• Versions
• Descriptions
• Installation paths
• Top-level documentation locations (e.g. README and CHANGELOG)

Retrieves detailed information about a specific gem, including:

• Version
• Description
• Installation path
• Top-level documentation locations
• Source code file locations

• BUNDLE_GEMFILE: Used by Bundler to locate your Gemfile. If you use th