bundler_mcp

# BundlerMCP 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/yjacquin/fast-mcp). [](https://github.com/subelsky/bundler_mcp/actions/workflows/main.yml) [](https://badge.fury.io/rb/bundler_mcp) ## Installation Install the gem and add to the application's Gemfile by executing: ```bash bundle add bundler_mcp --group=development ``` ## Usage 1. Generate the binstub: ```bash bundle binstubs bundler_mcp ``` 2. Configure your client to execute the binstub. Here are examples that work for Claude and Cursor: ### Basic Example (mcp.json) ```json { "mcpServers": { "bundler-mcp": { "command": "/Users/mike/my_project/bin/bundler_mcp" } } } ``` ### Example with logging and explicit Gemfile ```json { "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" } } } } ``` ### Documentation [Available on RubyDoc](https://www.rubydoc.info/gems/bundler_mcp/) ### Available Tools The server provides two tools for AI agents: #### list_project_gems Lists all bundled Ruby gems with their: - Versions - Descriptions - Installation paths - Top-level documentation locations (e.g. `README` and `CHANGELOG`)  #### get_gem_details Retrieves detailed information about a specific gem, including: - Version - Description - Installation path - Top-level documentation locations - Source code file locations  ## Environment Variables - `BUNDLE_GEMFILE`: Used by Bundler to locate your Gemfile. If you use the binstub method described in the [Usage](#usage) section, this is usually not needed. - `BUNDLER_MCP_LOG_FILE`: Path to log file. Useful for troubleshooting (defaults to no logging) ## Development After checking out the repo, run `bin/setup` to install dependencies and `bundle exec rspec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment. ### Testing with the MCP Inspector You can test the server directly using the [MCP inspector](https://modelcontextprotocol.io/docs/tools/inspector): ```bash # Basic usage npx @modelcontextprotocol/inspector ./bin/bundler_mcp # With logging enabled BUNDLER_MCP_LOG_FILE=/tmp/log/mcp.log npx @modelcontextprotocol/inspector ./bin/bundler_mcp # With custom Gemfile BUNDLE_GEMFILE=./other/Gemfile npx @modelcontextprotocol/inspector ./bin/bundler_mcp ``` ### Release Process To install this gem onto your local machine, run `bundle exec rake install`. To release a new version: 1. Update the version number in `version.rb` 2. Run `bundle exec rake release` This will: - Create a git tag for the version - Push git commits and the created tag - Push the `.gem` file to [rubygems.org](https://rubygems.org) ## Contributing Bug reports and pull requests are welcome on GitHub at https://github.com/subelsky/bundler_mcp. ## License Open source under the terms of the [MIT License](https://opensource.org/licenses/MIT). ## Author [Mike Subelsky](https://subelsky.com)