Rails MCP Server

Content

Rails MCP Server is a Ruby gem that gives Claude and other MCP clients a Rails-aware way to inspect configured projects. It exposes a compact MCP tool surface for switching projects, discovering available tools, invoking internal analyzers, and running constrained read-only Ruby helpers inside a Rails project context.

Use it when a coding assistant needs Rails-specific context such as routes, Active Record models, associations, validations, database schema, controllers, views, environment configuration, or framework guides without granting a broad shell server.

Source Review

• https://github.com/maquina-app/rails-mcp-server
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/README.md
• https://rubygems.org/api/v1/gems/rails-mcp-server.json
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/LICENSE.txt
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/rails-mcp-server.gemspec
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/lib/rails-mcp-server/tools/execute_ruby.rb
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/lib/rails-mcp-server/utilities/path_validator.rb
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/lib/rails-mcp-server/tools/switch_project.rb
• https://raw.githubusercontent.com/maquina-app/rails-mcp-server/main/docs/AGENT.md

These sources were reviewed on 2026-06-06. Prefer the live repository, README, RubyGems metadata, license, gemspec, Ruby execution tool, path validator, project-switching tool, and agent guide for current setup and operating details.

Features

• Configure multiple Rails projects through projects.yml or the rails-mcp-config terminal UI.
• Auto-detect a single Rails project from RAILS_MCP_PROJECT_PATH, current working directory, or single-project mode.
• Switch between configured projects with switch_project.
• Discover available analyzers with search_tools.
• Invoke internal analyzers through execute_tool.
• Inspect project overview, files, routes, database schema, models, controller and view relationships, and environment configuration.
• Analyze Active Record associations, validations, callbacks, scopes, and model methods.
• Load Rails, Turbo, Stimulus, Kamal, or custom documentation guides.
• Run constrained read-only Ruby snippets with helper methods such as read_file, file_exists?, list_files, and project_root.
• Start over stdio by default, or use HTTP/SSE mode for advanced local proxy workflows.
• Provide setup helpers for Claude Desktop and GitHub Copilot Agent workflows.

Installation

Install the gem:

gem install rails-mcp-server

Run the interactive configuration tool:

rails-mcp-config

Add the server to an MCP client:

{
  "mcpServers": {
    "railsMcpServer": {
      "command": "rails-mcp-server"
    }
  }
}

For a single project, set an explicit project path before starting the server:

{
  "mcpServers": {
    "rails": {
      "command": "rails-mcp-server",
      "env": {
        "RAILS_MCP_PROJECT_PATH": "ABSOLUTE_PATH_TO_RAILS_PROJECT"
      }
    }
  }
}

Use Cases

• Ask Claude to summarize a Rails application's structure before editing.
• Inspect routes, controllers, views, models, associations, validations, and database schema from one MCP workflow.
• Find files and read source through Rails-aware path validation.
• Load framework guides while implementing Rails, Turbo, Stimulus, or Kamal features.
• Query a Rails project with constrained read-only Ruby helpers instead of granting shell access.
• Support GitHub Copilot Agent or Claude Desktop with Rails-specific project context.

Safety and Privacy

Rails MCP Server is a local code and project-inspection tool. It can expose source code, routes, schema details, model relationships, configuration names, and framework docs to the MCP client. Scope it to one approved Rails project or a small reviewed project list, and avoid adding directories that contain secrets, logs, private customer data, dependency caches, or unrelated projects.

The execute_ruby tool is intentionally read-only and blocks common dangerous patterns, file writes, shell execution, network access, environment reads, and sensitive files. Treat those checks as defense in depth, not permission to run arbitrary unreviewed code in high-risk repositories.

Duplicate Notes

Existing catalog entries cover general code indexing, repository search, and editor-control tools. This entry covers the separate maquina-app/rails-mcp-server Ruby gem and its Rails-specific analyzers, project switching, guide resources, and read-only Ruby execution workflow.