How AgentCore Gateway supports the MCP 2026-07-28 spec

This article explains how AgentCore Gateway supports the MCP 2026-07-28 specification, the largest revision of the Model Context Protocol since its launch.

• MCP becomes stateless, eliminating session pinning and enabling horizontal scaling on standard HTTP infrastructure
• Protocol version, client info, and capabilities now travel in request headers and metadata instead of requiring initialization handshakes
• Routing, caching, and tracing work without parsing JSON-RPC bodies using standard HTTP headers like Mcp-Method and Mcp-Name
• Server-to-client interactions use Multi-Round-Trip Requests with opaque state tokens instead of persistent connections
• New extensions framework allows capabilities to evolve independently without breaking core protocol
• Authorization aligns with OAuth 2.0 and OpenID Connect production practices
• Transport and application error layers are cleanly separated with proper HTTP status codes
• Enable 2026-07-28 on AgentCore Gateway with a single UpdateGateway call supporting multiple versions simultaneously

The update is opt-in and backward-compatible, allowing clients and gateways to upgrade independently while supporting multiple protocol versions concurrently.