@@ -0,0 +1,69 @@
+---
+title: The Official Ruby SDK for MCP Reaches Tier 1
+date: "2026-09-29T09:00:00+00:00"
+publishDate: "2026-09-29T09:00:00+00:00"
+slug: ruby-sdk-tier-1
+description: The official Ruby SDK for the Model Context Protocol is now a Tier 1 SDK under the MCP SDK tiering system, with full support for the 2026-07-28 specification revision and a 100% conformance pass rate across both scored spec revisions.
+author:
+  - Koichi Ito (Ruby SDK Maintainer)
+tags:
+  - mcp
+  - sdk
+  - announcement
+  - ruby
+---
+
+The official [Ruby SDK](https://github.com/modelcontextprotocol/ruby-sdk) for the Model Context Protocol is now a Tier 1 SDK, as recorded in the [Tier 1 assessment](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/3247) under the [SDK tiering system](https://modelcontextprotocol.io/community/sdk-tiers). Ruby joins TypeScript, Python, C#, Go, and Rust as the sixth Tier 1 SDK, meeting the tier's requirements for full feature support, a 100% conformance pass rate, and a maintenance commitment with defined response times.
+
+## Full support for the 2026-07-28 revision
+
+[Version 1.2.0](https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v1.2.0) of the [`mcp` gem](https://rubygems.org/gems/mcp) completes support for the [2026-07-28 revision](/posts/2026-07-28/):
+
+- The stateless lifecycle (SEP-2575) is served alongside the classic session handshake, including `server/discover` and the `subscriptions/listen` notification stream
+- Multi round-trip requests (SEP-2322) work on both the server and the client, and a built-in shim lets handlers written in the new `input_required` style serve pre-2026 clients unchanged
+- Cache hints (SEP-2549) and the standard and custom HTTP request headers (SEP-2243) are emitted and validated on the modern path
+- Roots, Sampling, and Logging are marked deprecated per SEP-2577, and clients connecting with the 2026-07-28 protocol version warn when they declare the Roots or Sampling capabilities
+
+The server serves both lifecycle eras side by side, so current clients keep working while 2026-07-28 clients use the stateless path. See [Protocol Versions](https://ruby.sdk.modelcontextprotocol.io/protocol-versions/) for how the SDK handles each era. Several 1.x minor releases, starting with 1.2.0, tighten validation under the spec-conformance and security exceptions of the SDK's versioning policy, so review the [changelog](https://github.com/modelcontextprotocol/ruby-sdk/blob/main/CHANGELOG.md) when upgrading an existing 1.x application.
+
+## From Tier 2 to Tier 1
+
+The [Tier 2 assessment](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/3127) in July recorded two gaps on the path to Tier 1: documentation coverage and an agreed timeline for tracking new spec revisions. Since then:
+
+- The SDK passes 100% of the scored server and client conformance scenarios for both the 2025-11-25 and 2026-07-28 requirement sets, measured with the [conformance suite](https://github.com/modelcontextprotocol/conformance)'s frozen per-revision scoring: 67/67 server scenario runs and 50/50 client scenario runs, each executed at that revision's own wire version
+- Every implemented feature is documented with prose and examples, from non-text content types through elicitation options to the full OAuth client flow; with [version 1.3.0](https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v1.3.0), this documentation moved from the README to a revamped [documentation site](https://ruby.sdk.modelcontextprotocol.io), one page per topic
+- The repository maintained a 100% issue triage rate within the Tier 1 window, with no P0 issues filed
+
+The full evidence tables, including reproduction steps for the conformance results, are in the [Tier 1 assessment](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/3247).
+
+The stable release supporting 2026-07-28 shipped about two weeks after the specification release, while Tier 1 expects support by the release date. To close this spec-tracking gap, the Ruby SDK team has committed to supporting the next revision, currently scheduled for 2026-12-15, by its release date.
+
+The road here was short but steep: the SDK was assessed at [Tier 3](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/2340) in March 2026, reached [Tier 2](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/3127) with the 1.0 release in July, applied for Tier 1 in August, and was confirmed at Tier 1 in September.
+
+## Get started
+
+Install or upgrade the gem to the latest release ([v1.6.1](https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v1.6.1) at the time of writing):
+
+```console
+$ gem install mcp
+```
+
+If your Gemfile still pins the gem to a 0.x version, update the constraint to pick up the latest feature set:
+
+```ruby
+gem 'mcp', '>= 1.6'
+```
+
+or, to stay within the 1.x series:
+
+```ruby
+gem 'mcp', '~> 1.6'
+```
+
+If you are already running a 1.x server, upgrading lets it serve 2026-07-28 clients alongside existing ones. See the [Ruby SDK documentation](https://ruby.sdk.modelcontextprotocol.io) for guides on building servers and clients, including Rails integration, and the [1.0 announcement](/posts/ruby-sdk-1-0/) for a walkthrough of the basics.
+
+## Give us your feedback
+
+If 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, and with Tier 1 comes a commitment to triage them quickly.
+
+The Ruby SDK 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 from Tier 3 to Tier 1. Special thanks to [Felix Weinberger](https://github.com/felixweinberger) and [Paul Carleton](https://github.com/pcarleton) for their review and independent verification of the Tier 1 assessment, and to [Den Delimarsky](https://github.com/localden) for the final review.