API Gateway Brings MCP Support to Existing REST APIs in Public Preview

Google Cloud API Gateway has bridged the gap between enterprise capabilities and agents by enabling Model Context Protocol (MCP) tools. Previously, teams had to set up separate MCP servers to make REST APIs callable by agents, which involved implementing routing, authentication, and quota logic.

API Gateway now allows existing REST APIs to be exposed as agent-ready MCP tools with minimal setup. Users can annotate their OpenAPI spec, deploy it, and the API operations will become available as MCP tools without requiring a separate server.

The Public Preview of this feature supports REST and OpenAPI 3.x backends with current authentication. However, there are some limits to be aware of: operations returning empty bodies are not exposed, deeply nested object schemas may not render fully in tools/list, and a gateway serves up to 1,000 tools.

MCP support is available now in Public Preview. Users can check out the documentation and turn their first API into an agent-ready tool today.