mcp-rb

# MCP-RB A lightweight Ruby framework for implementing MCP (Model Context Protocol) servers with a Sinatra-like DSL. ## Installation Add this line to your application's Gemfile: ```ruby gem 'mcp-rb' ``` ## Usage Here's a simple example of how to create an MCP server: ```ruby require 'mcp' name "hello-world" version "1.0.0" # Define a resource resource "hello://world" do name "Hello World" description "A simple hello world message" call { "Hello, World!" } end # Define a resource template resource_template "hello://{user_name}" do name "Hello User" description "A simple hello user message" call { |args| "Hello, #{args[:user_name]}!" } end # Define a tool tool "greet" do description "Greet someone by name" argument :name, String, required: true, description: "Name to greet" call do |args| "Hello, #{args[:name]}!" end end # Define a tool with nested arguments tool "greet_full_name" do description "Greet someone by their full name" argument :person, required: true, description: "Person to greet" do argument :first_name, String, required: false, description: "First name" argument :last_name, String, required: false, description: "Last name" end call do |args| "Hello, First: #{args[:person][:first_name]} Last: #{args[:person][:last_name]}!" end end # Define a tool with an Array argument tool "group_greeting" do description "Greet multiple people at once" argument :people, Array, required: true, items: String, description: "People to greet" call do |args| args[:people].map { |person| "Hello, #{person}!" }.join(", ") end end ``` ## Supported specifications Reference: [MCP 2024-11-05](https://spec.modelcontextprotocol.io/specification/2024-11-05/) - [Base Protocol](https://spec.modelcontextprotocol.io/specification/2024-11-05/basic/) - ping - stdio transport - [Server features](https://spec.modelcontextprotocol.io/specification/2024-11-05/server/) - Resources - resources/read - resources/list - resources/templates/list - Tools - tools/list - tools/call Any capabilities are not supported yet. ## Testing ```bash rake test rake test:unit # run only the unit tests, skipping tests that test a running server ``` Test with MCP Inspector ```bash bunx @modelcontextprotocol/inspector $(pwd)/examples/hello_world.rb ``` ## Formatting ```bash bundle exec standardrb --fix ``` You can also use rake tasks: ```bash rake lint # Run standardrb to check code style rake lint:fix # Auto-fix standardrb issues ``` ## Release To release a new version: 1. Update version in `lib/mcp/version.rb` 2. Update `CHANGELOG.md` 3. Create a git tag ```bash git add . git commit -m "Release vx.y.z" git tag vx.y.z git push --tags ``` 1. Build and push to RubyGems ```bash gem build mcp-rb.gemspec gem push mcp-rb-*.gem ``` ## Changelog See [CHANGELOG.md](CHANGELOG.md)