MCP moves toward a stateless core
The final MCP 2026-07-28 specification shipped with a stateless core, multi round-trip requests, header-based routing, cacheable deterministic list results, authorization hardening, a formal extensions framework, a minimum deprecation window and updated Tier 1 SDKs. AWS AgentCore Gateway added opt-in support the same day.
Why it matters: MCP can now scale behind ordinary HTTP infrastructure while exposing routing and authorization information to gateways. The breaking transition removes implicit session state, so compatibility, external workflow state, cache correctness and authorization…