Stateless MCP in Python: The 2026-07-28 Handle Pattern

MCP just shipped its biggest revision since launch, and it changes how you deploy a server. The release candidate tagged 2026-07-28 was locked on May 21, 2026, and the final spec lands on July 28. The headline: MCP is now stateless at the protocol layer. The initialize handshake and the Mcp-Session-Id header are gone, so any request can land on any server instance.

Why this matters right now: SDK maintainers are validating against real workloads during the ten-week window before July 28, and Tier 1 SDKs are expected to ship support inside it. If you run a remote MCP server, the sticky sessions, shared session store, and gateway packet inspection you needed before are no longer required. This guide builds a working stateless endpoint from scratch in Python so you understand the wire format, not just an SDK call.