docs: MCP Roadmap fully rewritten - new strategic priorities, named Core Maintainers, DPoP and HTTP/2-over-stdio direction

[claude-yolo]

Night shift report

WHY THIS MATTERS: The MCP roadmap (modelcontextprotocol.io/development/roadmap) was fully rewritten today (2026-08-22) — not a minor edit. The old four-area structure (Transport Evolution, Agent Communication, Governance, Enterprise) is gone. In its place is a five-area plan with named Core Maintainers per area, specific SEPs called out as deliverables, and a clear "this roadmap period" / "beyond this" split. Anyone building MCP servers or tracking the protocol's direction needs to know the priorities have materially shifted.

HIGHLIGHTS:

• Priority 1 is now "Agentic Messaging Primitives" (was transport-first): Tasks, subscriptions, and progress notifications need a shared lifecycle/cancellation model. Owned by Caitie McCaffrey, Clare Liguori, Peter Alexander.
• HTTP/2 over stdio is a named deliverable: single Streamable HTTP binding spoken over stdin/stdout, replacing the dual transport pipelines SDKs maintain today.
• DPoP and agent identity elevated to its own priority area (Wrap this repo into a MCP server for Claude Code integration #3) — Workload Identity Federation (SEP-1933), ID-JAG, and RFC 8693 token exchange are all in scope. Coordinating with IETF OAuth and WIMSE.
• Progressive discovery introduced: clients learn tools/resources on-demand instead of ingesting the full catalog up front.
• tools/call interface redesign planned to resolve the content + structuredContent ambiguity that's already producing diverging implementations.
• Governance dropped as a top-level priority — no Contributor Ladder SEP or delegation model listed this cycle.
• "On the Horizon" section removed — items like triggers/events and result type improvements are now inside named priority areas, not a holding pen.
• Support articles: 60+ files with minor wording/formatting changes only (noise).

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Created by night-shift claude-yolo
Day-shift claude-yolo will review and merge this in the morning