Ground truth about your Rails app, for coding agents

A read-only MCP server that gives Cursor, Claude Code, Codex and other MCP clients your app’s real schema and routes, plus a Rails 8 skill that tells the agent to check them before it writes code.

Get started View on GitHub

Look it up instead of guessing

Agents writing Rails code guess all the time. Is it user.full_name or user.name? Is the column nullable? Is the helper post_comments_path or comments_path? Each wrong guess is broken code and another review round. rails-agent-kit lets the agent ask your app.

  • rails_schema: tables, columns, indexes and foreign keys from db/schema.rb, parsed statically. It never boots the app or connects to a database.
  • rails_routes: every route with its name, verb, path, controller#action and source line, from your app’s own bin/rails routes --expanded.
  • Rails 8 conventions skill: an Agent Skill for Cursor and Claude Code that tells the agent to call the tools before it edits code.
  • Read-only and local: a stdio server your client starts. It doesn’t listen on a network port.

Two minutes to set up 

gem install rails-agent-kit
claude mcp add rails-agent-kit -- rails-agent-kit --root /path/to/your/rails/app

That’s Claude Code. Getting started covers Cursor, Codex, Claude Desktop and running it through your app’s bundle.

What the agent sees

A real answer for the small blog app in the test fixtures, pretty-printed and trimmed:

// rails_routes { "filter": "comments" }
{
  "total": 7,
  "count": 2,
  "routes": [
    { "name": "post_comments", "verb": "POST", "path": "/posts/:post_id/comments(.:format)",
      "controller_action": "comments#create", "source_location": "config/routes.rb:3" },
    { "name": "post_comment", "verb": "DELETE", "path": "/posts/:post_id/comments/:id(.:format)",
      "controller_action": "comments#destroy", "source_location": "config/routes.rb:3" }
  ]
}

rails-agent-kit is early (v0.1.0), and the API may change before 1.0. Pages mark features that are on main but not yet released.