rubyllm-mcp

name	rubyllm/mcp
version	1.0.0
description	Model Context Protocol (MCP) client for RubyLLM. Use this skill when connecting RubyLLM to MCP servers for tools, resources, and prompts. Supports stdio, HTTP streaming, and SSE transports with OAuth 2.1 authentication.

RubyLLM::MCP v1.0.0

MCP for Ruby and RubyLLM

Ruby client for the Model Context Protocol (MCP), built to work with RubyLLM. Use MCP tools, resources, and prompts from your RubyLLM chats.

Gem Version: 1.0.0
Protocol: 2025-06-18 (stable), 2026-01-26 (draft)
GitHub: https://github.com/patvice/ruby_llm-mcp

Installation

gem 'ruby_llm-mcp'

Quick Start

require "ruby_llm/mcp"

RubyLLM.configure do |config|
  config.openai_api_key = ENV["OPENAI_API_KEY"]
end

# Create MCP client
client = RubyLLM::MCP.client(
  name: "filesystem",
  transport_type: :stdio,
  config: {
    command: "bunx",
    args: ["@modelcontextprotocol/server-filesystem", Dir.pwd]
  }
)

# Use MCP tools with RubyLLM
chat = RubyLLM.chat(model: "gpt-4.1-mini")
chat.with_tools(*client.tools)

chat.ask("Find Ruby files modified today and summarize what changed.")

Transports

STDIO (Local Processes)

client = RubyLLM::MCP.client(
  name: "filesystem",
  transport_type: :stdio,
  config: {
    command: "npx",
    args: ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/files"]
  }
)

HTTP Streaming

client = RubyLLM::MCP.client(
  name: "my-server",
  transport_type: :http_stream,
  config: {
    url: "http://localhost:3001/mcp"
  }
)

SSE (Server-Sent Events)

client = RubyLLM::MCP.client(
  name: "my-server",
  transport_type: :sse,
  config: {
    url: "http://localhost:3001/sse"
  }
)

Tools

# Get available tools
client.tools.each do |tool|
  puts tool.name
  puts tool.description
  puts tool.input_schema
end

# Use with RubyLLM
chat = RubyLLM.chat
chat.with_tools(*client.tools)
chat.ask("List files in current directory")

Resources

# List available resources
client.resources.each do |resource|
  puts resource.uri
  puts resource.name
  puts resource.description
end

# Read a resource
resource = client.resource("release_notes")
chat = RubyLLM.chat
chat.with_resource(resource)
chat.ask("Summarize release notes in 5 bullet points")

Prompts

# List available prompts
client.prompts.each do |prompt|
  puts prompt.name
  puts prompt.arguments
end

# Use a prompt
prompt = client.prompt("code_review")
chat = RubyLLM.chat

response = chat.ask_prompt(
  prompt,
  arguments: {
    language: "ruby",
    focus: "security"
  }
)

Handlers & Notifications

# Progress notifications
client.on_progress do |progress|
  puts "Progress: #{progress.progress}% - #{progress.message}"
end

# Logging notifications
client.on_logging do |logging|
  puts "[#{logging.level}] #{logging.message}"
end

# Resource updates
client.on_resource_updated do |uri|
  puts "Resource updated: #{uri}"
end

# Tool calls
chat = RubyLLM.chat
chat.with_tools(*client.tools)
chat.ask("Run a repository scan") do |chunk|
  print chunk.content
end

OAuth 2.1 Authentication

Rails Setup (Per-User)

# config/routes.rb
mount RubyLLM::MCP::OAuth::Engine, at: "/mcp/oauth"

# app/controllers/mcp_connections_controller.rb
class McpConnectionsController < ApplicationController
  def create
    client = RubyLLM::MCP.client(
      name: "github",
      transport_type: :http_stream,
      config: { url: "https://api.github.com/mcp" },
      oauth: {
        client_id: ENV["GITHUB_MCP_CLIENT_ID"],
        client_secret: ENV["GITHUB_MCP_CLIENT_SECRET"],
        redirect_uri: mcp_oauth_callback_url
      }
    )
    
    # Redirect user to authorization
    redirect_to client.oauth_authorization_url
  end
  
  def callback
    client.complete_oauth(params[:code])
    # Save client.connection for current_user
  end
end

CLI Setup (Browser Flow)

client = RubyLLM::MCP.client(
  name: "github",
  transport_type: :http_stream,
  config: { url: "https://api.github.com/mcp" },
  oauth: {
    client_id: ENV["GITHUB_MCP_CLIENT_ID"],
    redirect_uri: "http://localhost:3000/callback"
  }
)

# Opens browser for authorization
client.oauth_interactive_auth

Protocol Tracks

# Stable track (default)
client = RubyLLM::MCP.client(
  name: "server",
  protocol_track: :stable  # 2025-06-18
)

# Draft track
client = RubyLLM::MCP.client(
  name: "server",
  protocol_track: :draft  # 2026-01-26
)

Common MCP Servers

Filesystem

npx @modelcontextprotocol/server-filesystem /path/to/files

client = RubyLLM::MCP.client(
  name: "filesystem",
  transport_type: :stdio,
  config: {
    command: "npx",
    args: ["@modelcontextprotocol/server-filesystem", Rails.root]
  }
)

GitHub

npx @modelcontextprotocol/server-github

PostgreSQL

npx @modelcontextprotocol/server-postgres postgres://localhost/mydb

Git

npx @modelcontextprotocol/server-git

Error Handling

begin
  client = RubyLLM::MCP.client(...)
  client.tools
rescue RubyLLM::MCP::ConnectionError => e
  Rails.logger.error "MCP connection failed: #{e.message}"
rescue RubyLLM::MCP::ProtocolError => e
  Rails.logger.error "MCP protocol error: #{e.message}"
end

See Also

• Main RubyLLM: rubyllm
• Tools: tools
• MCP Spec: https://modelcontextprotocol.io