Largest MCP Revision Goes Stateless, Drops Initialize Handshake and Session IDs
dfinke · x · 2026-07-22
The Model Context Protocol (MCP) is finalizing its largest spec update to date on July 28, headlined by a shift from a stateful to a stateless architecture.
Key changes include:
- Dropping the initialize handshake entirely (SEP-2575)
- Removing the Mcp-Session-Id header (SEP-2567)
- Requiring every request to carry its own protocol version, client info, and capabilities inline via meta, alongside new Mcp-Method and Mcp-Name headers for routing.
Related event: MCP Protocol's Largest Update: Shifting to Stateless on July 28(9 posts)→
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