MCP 2026-07-28: The Stateless Core That Made MCP Serverless
The MCP spec 2026-07-28, released July 28, 2026 by the Agentic AI Initiative under the Linux Foundation, is the fifth spec release and the one that made MCP serverless: the stateless core removes the initialize/initialized handshake and Mcp-Session-Id, moves method routing into Mcp-Method and Mcp-Name HTTP headers, and adds per-request _meta plus ttlMs/cacheScope caching. It also brings MRTR (SEP-2322), a Tasks extension (SEP-2663), and auth hardening via RFC 9207 and RFC 8707, alongside a deprecation policy for roots, sampling, and logging. Adoption has scaled to roughly 400M+ monthly SDK downloads, about 4x this year, near 250M per week.