Beta SDKs for the MCP 2026-07-28 Spec Release Candidate Are Here — Python, TypeScript, Go, and C# Ready

What's new

• Beta SDK releases: Python, TypeScript, Go, and C# SDKs now include support for the MCP 2026-07-28 release candidate spec.
• Stateless core: Servers can run behind a round-robin load balancer — no sticky sessions or shared session stores required.
• Mcp-Method header routing: New Mcp-Method and Mcp-Name headers replace session IDs for stateless routing.
• TTL tool list caching: Clients can cache tools/list responses per server's ttlMs setting.
• MCP Apps extension: Sandboxed HTML UI components natively in the MCP protocol.

Why it matters

The final MCP 2026-07-28 spec ships July 28. Teams building MCP servers or integrating MCP clients must test these beta SDKs now — backward compatibility with the old sessionful architecture will not be maintained. Breaking changes include: Initialize/initialized handshake removed, tasks/list endpoint removed, and error code change for missing resources.

How to try it

• Python: pip install mcp[beta] (version with 2026-07-28 RC support)
• TypeScript: npm install @modelcontextprotocol/sdk@beta
• Tier 1 SDK maintainers expected to ship final support within 10 weeks of spec publication