{"slug": "the-official-ruby-sdk-for-mcp-reaches-1-0", "title": "The Official Ruby SDK for MCP Reaches 1.0", "summary": "Version 1.0.0 of the official Ruby SDK for the Model Context Protocol is now available, marking the first stable release of the mcp gem with a stable public API and Semantic Versioning. The SDK now meets every Tier 2 requirement of the SDK tiering system, passing 100% of server and client conformance scenarios, and implements the 2025-06-18 and 2025-11-25 specification revisions. The release includes MCP servers with tools, prompts, resources, and more, plus a client with complete OAuth flow and stdio and Streamable HTTP transports.", "body_md": "[Version 1.0.0](https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v1.0.0) of the official [Ruby SDK](https://github.com/modelcontextprotocol/ruby-sdk) for the Model Context Protocol is now available. This is the first stable release of the [ mcp gem](https://rubygems.org/gems/mcp): the public API is now stable, and breaking changes ship only in major releases, following the Semantic Versioning policy documented in\n\n[VERSIONING.md](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/VERSIONING.md).\n\nAlongside the release, the Ruby SDK now meets every Tier 2 requirement of the [SDK tiering system](https://modelcontextprotocol.io/community/sdk-tiers), as recorded in the [Tier 2 assessment](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/3127), and development toward Tier 1 is ongoing.\n\n## What is in 1.0[#](#what-is-in-10)\n\nThe 1.0 release implements the 2025-06-18 and 2025-11-25 specification revisions and passes 100% of the server and client conformance scenarios. It includes:\n\n- MCP servers with tools, prompts, resources (including templates and subscriptions), completions, logging, pagination, progress, and cancellation, plus server-to-client requests for sampling, elicitation (form and URL mode), and roots\n- An MCP client with a complete OAuth flow, including dynamic client registration, PKCE, and scope handling\n- stdio and Streamable HTTP transports; the HTTP transport is a standard Rack app, so it can be mounted directly in Rails routes or any Rack-compatible framework\n\n## From Tier 3 to Tier 2[#](#from-tier-3-to-tier-2)\n\nThe Ruby SDK was assessed at [Tier 3](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/2340) in March 2026. Since then:\n\n- Server conformance moved from 83.3% to 100%, with no baselined failures\n- A conformance client was implemented and passes 100% of client scenarios\n- Sampling, elicitation, and progress notifications were implemented on both the server and client sides\n[ROADMAP.md](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/ROADMAP.md)and[VERSIONING.md](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/VERSIONING.md)were published\n\nWork is also under way to support the upcoming [2026-07-28 specification release](/posts/sdk-betas-2026-07-28/).\n\n## Get started[#](#get-started)\n\nInstall the gem:\n\n``` bash\n$ gem install mcp\n```\n\nA minimal stdio server looks like this:\n\n```\nrequire \"mcp\"\n\nclass ExampleTool < MCP::Tool\n  description \"A simple example tool that echoes back its arguments\"\n  input_schema(\n    properties: {\n      message: { type: \"string\" },\n    },\n    required: [\"message\"]\n  )\n\n  class << self\n    def call(message:, server_context:)\n      MCP::Tool::Response.new([{\n        type: \"text\",\n        text: \"Hello from example tool! Message: #{message}\",\n      }])\n    end\n  end\nend\n\nserver = MCP::Server.new(\n  name: \"example_server\",\n  tools: [ExampleTool],\n)\n\nMCP::Server::Transports::StdioTransport.new(server).open\n```\n\nSee the [Ruby SDK documentation](https://ruby.sdk.modelcontextprotocol.io) for guides on building servers and clients, including Rails integration.\n\n## Give us your feedback[#](#give-us-your-feedback)\n\nIf you run into problems or unexpected behavior while using the SDK, please report them on the [issue tracker](https://github.com/modelcontextprotocol/ruby-sdk/issues). Reports from real-world usage are especially valuable.\n\nThe Ruby SDK began at [Shopify](https://www.shopify.com/) and is maintained by [Topher Bullock](https://github.com/topherbullock), [Koichi Ito](https://github.com/koic), [Ateş Göral](https://github.com/atesgoral), and [Jonathan Hefner](https://github.com/jonathanhefner) together with the wider Ruby community. Thank you to everyone for the feedback and contributions on the road to 1.0.", "url": "https://wpnews.pro/news/the-official-ruby-sdk-for-mcp-reaches-1-0", "canonical_source": "https://blog.modelcontextprotocol.io/posts/ruby-sdk-1-0/", "published_at": "2026-07-27 09:00:00+00:00", "updated_at": "2026-08-22 10:14:40.230426+00:00", "lang": "en", "topics": ["developer-tools", "ai-infrastructure", "ai-tools"], "entities": ["Model Context Protocol", "Ruby SDK", "mcp gem", "Shopify", "Topher Bullock", "Koichi Ito", "Ateş Göral", "Jonathan Hefner"], "alternates": {"html": "https://wpnews.pro/news/the-official-ruby-sdk-for-mcp-reaches-1-0", "markdown": "https://wpnews.pro/news/the-official-ruby-sdk-for-mcp-reaches-1-0.md", "text": "https://wpnews.pro/news/the-official-ruby-sdk-for-mcp-reaches-1-0.txt", "jsonld": "https://wpnews.pro/news/the-official-ruby-sdk-for-mcp-reaches-1-0.jsonld"}}