Vercel MCP now supports the 2026-07-28 MCP specification

Vercel MCP now supports the 2026-07-28 MCP specification. The update lands on the same endpoint that already served the 2025 protocol, so deployments do not need a second URL or a cutover window. Newer clients pick up a stateless request model and updated authorization behavior without any client-side code change. Clients still on the 2025 protocol continue to work exactly as they did before.

Both protocol versions are served through the official MCP SDK v2 and mcp-handler 2.x. That stack is what lets one endpoint speak two dialects: the older stateful path for 2025 clients and the newer stateless request model for clients that implement the 2026-07-28 specification. Authorization behavior is part of that newer surface, so auth handling differs by which protocol version the client negotiates rather than by which host or path it hits.

For engineers wiring AI clients into Vercel, the practical win is zero migration work on the client. You do not fork configs, bump a client-side protocol flag, or maintain two MCP endpoints. Build against the 2025 protocol and keep shipping; adopt a client that understands 2026-07-28 and you get the stateless model and new auth behavior automatically. The server-side constraint is clear: stay on MCP SDK v2 and mcp-handler 2.x if you want that dual-protocol path.

Serving both versions from one endpoint is a compatibility strategy aimed at mixed fleets. Teams often run older agents, IDEs, or internal tools next to newer MCP clients; a hard version drop would force a coordinated upgrade. Vercel’s approach keeps the 2025 installed base live while the 2026-07-28 surface becomes available to clients that already speak it. That reduces the usual protocol-upgrade tax of dual deployments, temporary redirects, and version pinning across environments.

What to watch next is client uptake of the 2026-07-28 specification and how quickly your own tooling chain exposes the stateless request model and updated authorization path. If you control the MCP client, verify it can negotiate the newer protocol so you actually receive those behaviors rather than silently staying on 2025. If you only operate the Vercel MCP side, confirm you are on MCP SDK v2 and mcp-handler 2.x and that a single endpoint is enough for both client generations in your fleet.