MCP Becomes Stateless

The MCP 2026-07-28 Release Candidate has been released. This update is a major revision that transitions the core of the protocol to Stateless, designed to scale at large volumes on standard HTTP infrastructure.

Key Changes:

• Transition to Stateless Protocol: Session management has been removed from the protocol layer. MCP servers can now operate behind round-robin load balancers without sticky sessions or shared session stores, allowing for easy scaling through standard HTTP infrastructure.
• Removal of Handshake and Session: The existing initialize/initialized handshake has been removed. Protocol version, client information, and capabilities are now included in the _meta field of every request.
• Redesign of Server-Client Request Structure: Introduced the InputRequiredResult format, allowing servers to request input from clients without maintaining persistent connections (SSE streams).

Practical Impact: Previously, deploying MCP servers required complex session management and deep packet inspection by gateways. Now, efficient deployment and scaling are possible even in simple HTTP environments. Additionally, by having models pass explicit handles (e.g., basket_id) between tool calls, more robust and visible state management can be performed at the application level.