mcp_rails_template
by: seuros
A minimal Rails API template for creating MCP (Model Context Protocol) servers with robust tool execution capabilities and examples.
📌Overview
Purpose: ActionMCP serves as a framework that facilitates the integration and use of model context protocols in Ruby on Rails applications.
Overview: This document provides instructions and examples for setting up a Ruby on Rails application that incorporates the ActionMCP engine, enabling developers to leverage model context protocols effectively.
Key Features:
-
Integration Example: A straightforward demonstration of integrating the ActionMCP engine within a Ruby on Rails application, allowing for practical application of the framework.
-
Interactive Linter Tool: Includes functionality for linting Ruby code using RuboCop through ActionMCP, enhancing code quality and development efficiency.
Action MCP Example 🚀
A simple Ruby on Rails application demonstrating how to integrate and use the ActionMCP gem. The gem source code is available on GitHub at https://github.com/seuros/action_mcp.
This application showcases how to define and use MCP components within a Rails project.
Requirements
- Ruby (see
.ruby-version
for recommended version) - PostgreSQL (or Docker)
Getting Started
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 necessary values according to your setup (especially any required API keys for tools like fetch_weather_by_location_tool
).
3. Database Setup
You can quickly spin up a temporary PostgreSQL instance using Docker:
make up
This will start PostgreSQL on port 5466
.
Alternatively, configure your own PostgreSQL database by editing config/database.yml
.
4. Run the Application
Launch the Rails server:
bin/rails s
The app will be available at http://localhost:3002.
ActionMCP Engine
The ActionMCP engine is mounted at /action_mcp
. You can mount it at a custom location by modifying the routes in your application.
MCP Components (app/mcp/
)
This application includes several examples of ActionMCP components:
Prompts (app/mcp/prompts/
)
epic_adventure_prompt.rb
: Generates a short, narrative adventure story based on a provided hero name and adventure type (fantasy, sci-fi, mystery). It can optionally include a placeholder image data string.
Resource Templates (app/mcp/resource_templates/
)
gemfile_template.rb
: Provides access to the project's Gemfile dependencies as a JSON resource. It uses Bundler to fetch gems based on the specified environment (production
,test
,development
, ordefault
). The resource URI follows the patterngemfile://{environment}
.
Tools (app/mcp/tools/
)
Tools define specific actions that a language model can request to be executed.
dependency_info_tool.rb
: Retrieves dependency information using Bundler from theGemfile
andGemfile.lock
. It also checks for a.gemspec
file for runtime dependencies. Outputs separate JSON resources forproduction
,test
, andruntime
dependencies.fetch_weather_by_location_tool.rb
: Fetches weather forecast data from the Open-Meteo API (https://api.open-meteo.com
) based on provided latitude and longitude coordinates. Returns the raw JSON response from the API.rubocop_tool.rb
: Analyzes a provided Ruby code snippet using the RuboCop gem's API. Reports any detected style or code quality offenses, including the rule name, message, line, and column number.ruby_code_analyzer_tool.rb
: Performs basic static analysis of Ruby code within the project directory. Indexes classes, modules, and methods by parsing.rb
files. Can be queried to list all found classes, modules, or methods, or to get details (including source snippets) for a specific class/module (constant
) or method (method_details
).
Usage
To test and inspect MCP functionality interactively, you can use the MCP Inspector:
npx @modelcontextprotocol/inspector --url http://localhost:3002/action_mcp
Make sure your Rails server (bin/rails s
) is running before executing the inspector command.
Contributing
Feel free to contribute! Open issues or submit pull requests to help improve this example.
Happy Coding! ✨🚀