Turn your REST APIs into MCP tools with Google Cloud API Gateway- Google Developers Blog

This post introduces the integration of Google Cloud API Gateway with the Model Context Protocol (MCP) in Public Preview. It details how API Gateway can act as a remote MCP server by annotating OpenAPI specifications, enabling existing REST APIs to be exposed as agent-ready tools. The post explains the 'how it works' by describing the transcoding of MCP JSON-RPC requests to REST requests, the application of existing policies, and the translation of responses. It provides code examples for annotating OpenAPI specs, deploying the gateway, securing tool discovery with JWTs, and connecting an agent using the ADK. Key benefits highlighted include discoverability via API Hub and Agent Registry, and the elimination of separate MCP server operations by leveraging existing gateway infrastructure, authentication, quotas, and logging. The post also mentions roadmap items like resource and prompt support, response streaming, and Model Armor payload inspection, along with current limitations.