MCP Rails Template

🚀 Action MCP Example

A simple Ruby on Rails application demonstrating how to integrate and use the ActionMCP gem. The source code of this gem can be found on GitHub: https://github.com/seuros/action_mcp.

This application showcases how to define and use MCP components in a Rails project.

🚀 Quick Start

✨ Features

This application demonstrates how to define and use MCP components in a Rails project, and showcases the integration and usage of the ActionMCP gem.

📦 Installation

Requirements

• Ruby (see .ruby-version for the recommended version)
• PostgreSQL (or Docker)

Steps

1. Clone and Setup

git clone https://github.com/seuros/mcp_rails_template.git
cd mcp_rails_template
bin/setup

2. Environment Configuration Copy the provided .env.example file:

cp .env.example .env

Edit .env and fill in the necessary values (especially any API keys required for tools like fetch_weather_by_location_tool). 3. Database Setup You can use Docker to quickly start a temporary PostgreSQL instance:

make up

This will start PostgreSQL on port 5466. Alternatively, configure your own PostgreSQL database by editing config/database.yml. 4. Run the Application Start the Rails server:

bin/rails s

The application will be accessible at http://localhost:3002.

💻 Usage Examples

ActionMCP Engine

The ActionMCP engine is mounted at /action_mcp. You can mount it at a custom location by modifying the routes.

MCP Components (app/mcp/)

This application contains multiple examples of ActionMCP components:

• Prompts (app/mcp/prompts/)
  • epic_adventure_prompt.rb: Generates a short narrative adventure story based on the provided hero name and adventure type (fantasy, science fiction, mystery). It optionally includes a placeholder image data string.
• Resource Templates (app/mcp/resource_templates/)
  • gemfile_template.rb: Provides project Gemfile dependencies as a JSON resource. It uses Bundler to fetch gems based on the specified environment (production, test, development, or default). The resource URI follows the pattern gemfile://{environment}.
• Tools (app/mcp/tools/) Tools define specific actions that the language model can request to execute.
  • dependency_info_tool.rb: Retrieves dependency information from the Gemfile and Gemfile.lock using Bundler. It also checks for the existence of a .gemspec file for runtime dependencies. It outputs separate JSON resources for production, test, and runtime dependencies.
  • fetch_weather_by_location_tool.rb: Fetches weather forecast data for a specified latitude and longitude coordinate from the Open - Meteo API (https://api.open-meteo.com). It returns the raw JSON response from the API.
  • rubocop_tool.rb: Analyzes a provided Ruby code snippet using the RuboCop gem's API. It reports any detected style or code quality violations, including the rule name, message, line number, and column number.
  • ruby_code_analyzer_tool.rb: Performs basic static analysis on Ruby code in the project directory. It indexes classes, modules, and methods by parsing .rb files. It can query to list all found classes, modules, or methods, or get detailed information about a specific class/module (constant) or method (method_details).

Testing MCP Functionality

To interactively test and inspect MCP functionality, you can use the MCP inspector:

npx @modelcontextprotocol/inspector --url http://localhost:3002/action_mcp

Make sure the Rails server (bin/rails s) is running before executing the inspector command.

📄 License

No license information provided in the original document, so this section is skipped.

🔧 Technical Details

No specific technical implementation details (more than 50 words) provided in the original document, so this section is skipped.

🤝 Contribution

Contributions are welcome! Please submit issues or pull requests on GitHub to help improve this project.