MCP's new specification drops session state

The Agentic AI Foundation finalised a new Model Context Protocol specification, the largest revision to the standard since its original release. The update removes session state from the protocol layer entirely, replacing the sticky connections and shared session stores that production deployments have relied on with explicit handles — identifiers such as a workflow run ID that a tool can return directly, reason about and pass forward through later steps.

The specification also adds multi round-trip requests, header-based routing, cacheable list results, stronger authorisation requirements and a formal framework for extensions, alongside updated software development kits for the protocol's primary supported languages.

Removing statefulness lets integrations that once needed sticky sessions run on ordinary HTTP infrastructure, lowering the bar for operating MCP servers at scale.