MCP Ruby SDK cuts its first stable release, adds 2026-07-28 support, and is promoted to Tier 2

The MCP Ruby SDK closed out July with three milestones in ten days. On July 24 it published v1.0.0, its first stable release, declaring that the public API is now stable and breaking changes ship only in major releases; the release adds a ROADMAP.md outlining the path toward SEP-1730 and a VERSIONING.md. Notably, v1.0.0 makes no claim about the 2026-07-28 revision.

That support arrived a week later: v1.1.0, published August 1, adds 2026-07-28 as the latest protocol version (PR #476), four days after the revision shipped, alongside exposing server tool annotations on MCP::Client::Tool.

The tier promotion followed on August 2, when spec repo PR #3128, "Add Ruby SDK Tier 2 assessment to SDK listing", merged. The diff moves the Ruby SDK's badge from Tier 3 to Tier 2 in both the 2026-07-28 and draft SDK listings, placing it alongside Java and Rust in the middle tier below the four Tier 1 SDKs (TypeScript, Python, Go, C#). Per the tiering policy, Tier 2 requires an 80% conformance test pass rate, new protocol features within six months, issue triage within a month, critical bug resolution within two weeks, at least one stable release, basic documentation, a published dependency policy, and a published plan toward Tier 1.

The month bookends neatly against the SDK's rockier start: its five July 8 security advisories, all fixed in v0.23.0, preceded the stable line by under three weeks.