MCP's 2026-07-28 spec goes stateless: no sessions, edge-ready
The biggest MCP change since launch: request/response replaces sessions, MCP Apps render UI in chat, tunnels reach private servers, and OAuth gets hardened.
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Sessions are gone — MCP is request/response now
The initialize/initialized handshake and the Mcp-Session-Id header are out; every request now carries its own protocol version, client identity and capabilities in _meta. You can run MCP servers behind plain round-robin load balancers on serverless or edge, with no shared session store.
MCP Apps put interactive UI inside the chat
Servers can now render buttons, forms and dashboards directly in the conversation — no tab-switching. Tasks also graduates to a formal io.modelcontextprotocol/tasks extension with poll-based tasks/get and a new tasks/update for long-running work.
MCP Tunnels reach private servers (research preview)
Connect Claude to servers on an internal network with no public internet exposure, firewall holes or IP allowlists. It's the piece that lets you wire internal tools into Claude without shipping them to the open web.
OAuth hardening: RFC 9207, and DCR is on the way out
Auth servers must now return iss and clients must validate it, closing authorization-server mix-up attacks; Dynamic Client Registration is deprecated in favor of Client ID Metadata Documents; clients declare application_type for CLI and desktop localhost redirects. Enterprise admins provision connectors once and users inherit access via identity groups on Entra or Okta.
What breaks — and your 12-month clock
Roots, Sampling, Logging and the legacy HTTP+SSE transport are deprecated, but a new 12-month minimum window means they keep working for at least a year. All four Tier-1 SDKs — TypeScript, Python, Go and C# — support the spec today; Rust is in beta. If you leaned on session IDs, that's the main thing to migrate.
The ecosystem you're building into
Claude's connectors directory now lists 950+ MCP servers, and MCP has crossed 400M monthly SDK downloads — a 4x jump this year. Support is rolling out across Claude products now.