The SDK tracks implementation of MCP spec components via GitHub Projects, with a dedicated project board for each spec revision:
- 2026-07-28 spec revision board — implemented in v2.0.0 (released 2026-07-27, alongside the spec).
- 2025-11-25 spec revision board — implemented in v1.23.0 (2025-11-25) and carried into v2, minus the experimental tasks component (SEP-1686), which v2 does not serve.
Conformance against the 2025-11-25 and 2026-07-28 revisions runs on each push to main (and against 2025-11-25 on v1.x) via the conformance workflow using the MCP conformance suite.
v2.0.0 is the stable release line (main). Post-release work is tracked as issues on this repository and released as 2.x patch and minor releases (see VERSIONING.md):
- Migration tooling and guides (
@modelcontextprotocol/codemod,docs/migration/). - Runtime coverage beyond Node.js (Bun, Deno, Cloudflare Workers, Vercel) and the framework integrations (
node,express,hono,fastify). - Documentation completeness for every non-experimental spec feature at https://ts.sdk.modelcontextprotocol.io/v2/.
The next MCP specification revision is being developed in the protocol repository. The SDK implements accepted SEPs as they are finalized so that support ships with the spec release, with a dedicated project board tracking component-level progress for that revision.
Protocol extensions are implemented as they stabilize and are not part of the core tier requirements:
- Tasks (
io.modelcontextprotocol/tasks) — #2189. - Client authentication extensions: Workload Identity Federation (SEP-1933) — #2576; DPoP (SEP-1932).
The v1.x branch (@modelcontextprotocol/sdk) continues to receive bug fixes and security updates for at least six months after the v2 release (2026-07-27). It targets the 2025-11-25 spec revision; new spec revisions are implemented on main only.