MCP 2026-07-28 Specification: transport going stateless

# Summary The Model Context Protocol (MCP) specification version 2026-07-28 introduces a major shift from a stateful bidirectional protocol to a stateless request/response model, addressing developer demands for improved reliability and scalability. Key improvements include self-describing requests that work with load balancers, header-based routing for gateways, elimination of bidirectional streams through Multi Round-Trip Requests, and caching capabilities for tool catalogs. The update also formalizes an extensions framework, strengthens authorization security, and establishes a twelve-month deprecation policy, with updated SDKs in TypeScript, Python, Go, and C#.