MCP's Biggest Spec Change Since Launch Ditches the Session
The Model Context Protocol's 2026-07-28 specification, nicknamed Stateless MCP, is the largest change to the MCP spec since it launched and lets servers operate without maintaining session state.
What it is
The 2026-07-28 Model Context Protocol specification update, informally called Stateless MCP, revises how MCP servers can expose tools to LLM agent frameworks without requiring a persistent session.
What it does
It changes the core interaction model so an MCP server no longer has to hold state across a session, which Simon Willison says reignited his interest in the protocol enough to build new tools like llm-mcp-client and datasette-mcp around it.
Why it matters
Stateless servers are simpler to deploy, scale, and reason about than session-based ones, an alternative to the original MCP model that required servers to track conversational state per client.
How to use it
Read the 2026-07-28 spec announcement if you maintain an MCP server, since existing stateful servers may need updates to work with clients built against the new spec.
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