MCP just deleted its session handshake

MCP just deleted its session handshake. That one change does more for enterprise agent deployment than any model release this month.

The 2026-07-28 spec drops the initialize/initialized handshake and the Mcp-Session-Id header. Protocol version and capabilities now ride in _meta on every request, and a new server/discover method covers the rest.

What that buys you is a tool server you can put behind a plain round-robin load balancer. No session affinity to maintain, so you can drop the shared session store your horizontal deployment needed. Proxies route on the Mcp-Method header instead of inspecting bodies. Your MCP fleet becomes an ordinary stateless HTTP service, which is the only shape most platform teams will agree to run.

Roots, Sampling and Logging are deprecated in the same release. Annotation-only, still functional through 2027. Logging moves to stderr and OpenTelemetry.

The trap: read the Sampling deprecation carefully. If your tool server calls back through the client for model access, the replacement is a direct provider API from inside the server. In an air-gapped or egress-controlled estate that is a network and procurement change, not a code change.

Your tool servers just became ordinary web services. Deploy them like it.