Summary
An agent can check the version you actually have before writing code against it.
It closes the gap between what a model remembers about a gem and what your lockfile resolved: the versions are yours, and the paths let it read the installed source and CHANGELOG rather than recall an API.
What it is
A Ruby gem that runs as an MCP server over your project's Gemfile. It reports the gems Bundler resolved, with versions, descriptions, install paths and the location of each gem's README and CHANGELOG.
What you get
- Every bundled gem, with version, description, install path and top-level documentation locations
- One gem in detail, including where its source files live on disk
Requirements
Ruby, with the gem added to the development group and a binstub generated by bundle binstubs. Point your client at that binstub; an environment variable selects a different Gemfile when the binstub is not enough.
Setup effort
One command — npx @modelcontextprotocol/inspector ./bin/bundler_mcp