VercelEngineering PostOfficial Source

Latest MCP spec now supported in mcp-handler

mcp-handler 2.0 adds the stateless 2026 MCP protocol and SDK v2 while keeping 2025 Streamable HTTP clients working, but drops HTTP+SSE and raises upgrade requirements.

Vercel · Jul 30, 2026

Open Source Open Markdown Open JSON

Source Summary

**mcp-handler 2.0.0** supports the **2026-07-28 MCP specification** and MCP TypeScript SDK v2. It serves the new stateless protocol alongside a compatibility layer for 2025-era Streamable HTTP, without Redis or session storage.

Practical Implication

Builders can migrate servers while existing stateless clients keep using the same endpoint. Budget time to move definitions to SDK v2 registration APIs and Standard Schema inputs, and replace @modelcontextprotocol/sdk with @modelcontextprotocol/server.

Agent-Ready Context

**mcp-handler 2.0.0** supports the **2026-07-28 MCP specification** and MCP TypeScript SDK v2. It serves the new stateless protocol alongside a compatibility layer for 2025-era Streamable HTTP, without Redis or session storage.

Builders can migrate servers while existing stateless clients keep using the same endpoint. Budget time to move definitions to SDK v2 registration APIs and Standard Schema inputs, and replace @modelcontextprotocol/sdk with @modelcontextprotocol/server.

The upgrade requires **Node.js 20 or later** and zod 4. HTTP+SSE is removed: /sse and /message return **410 Gone**, so clients tied to that transport must remain on 1.x until they move to Streamable HTTP.

Connected Context · Feed7 Judgment

This turns the surrounding growth in MCP-powered browsing, deployment, purchasing, and remote agents into a concrete server migration boundary. It preserves one endpoint for stateless Streamable HTTP clients, but narrows compatibility sharply: SDK v2, Standard Schema, Node.js 20, and zod 4 become prerequisites, while HTTP+SSE clients cannot upgrade until they change transport.

Vercel MCP can now deploy codeDeployment is a state-changing MCP capability whose server can adopt the new handler while retaining compatible stateless clients on the same endpoint.Vercel MCP now supports purchasesPurchase tooling raises the implementation stakes of the protocol migration because transport compatibility must be preserved without weakening its existing confirmation boundary.Expanding Managed Agents in Gemini API: background tasks, remote MCP and moreManaged Agents are a remote MCP client use case; the compatibility layer reduces migration disruption only if those clients use stateless Streamable HTTP rather than removed HTTP+SSE.ChromeDevTools/chrome-devtools-mcpChrome DevTools MCP exemplifies the tool servers affected by the move to SDK v2 registration and Standard Schema inputs.

Context Map

contextcoding#mcp#tool-use#context-engineering

Uncertainty

The upgrade requires **Node.js 20 or later** and zod 4. HTTP+SSE is removed: /sse and /message return **410 Gone**, so clients tied to that transport must remain on 1.x until they move to Streamable HTTP.