MCP 2026-07-28 from the server side: Codex already speaks it, Claude doesn't yet

On July 28, the Model Context Protocol project shipped a new spec revision, 2026-07-28 . I run backend engineering at GoodBarber, and our public MCP server is a live production surface: real apps, real content, real push notifications. So for us a new revision is not a changelog to skim on a Friday. It is a migration with our name on it. We have just brought the server up to the new revision. This post is three things: the operator's cut of what changed, what upgrading a public server actually involves, and the thing we found in our logs while checking the work. The last one is the reason I'm writing. The operator's cut of 2026-07-28 The headline is the stateless core. MCP grew up as a stateful, bidirectional protocol: an initialize handshake, a negotiated session, an Mcp-Session-Id header to carry it all. The new revision retires that entirely. Every request now self-describes in _meta : protocol version, client identity, capabilities. The practical consequence is the one server operators have wanted since day one: you can put an MCP server behind a plain round-robin load balancer with no shared session storage. If you have ever kept session affinity alive with duct tape, you know exactly which muscle just relaxed. The rest, fast: Method and tool names now also travel in Mcp-Method and Mcp-Name HTTP headers, so gateways can route and meter without parsing JSON bodies. Multi Round-Trip Requests: a call can come back with resultType: "input_required" and continue over stateless connections. Mid-call questions no longer need a held-open stream. List results (tools, prompts, resources) carry ttlMs and cacheScope , so clients can finally cache your inventory honestly instead of guessing. Authorization hardening: RFC 9207 issuer validation, and Client ID Metadata Documents replacing Dynamic Client Registration. Tasks, MCP Apps, and Enterprise Managed Authorization become formal extensions instead of core features. Roots, Sampling, and Logging are deprecated, with a minim