Google Cloud API Gateway can now turn REST APIs into MCP tools
In short: Google Cloud API Gateway now supports acting as a remote MCP server in Public Preview. By annotating an existing OpenAPI spec (x-google-api-management.mcp and x-google-mcp-tool), teams can expose their current REST operations as agent-ready MCP tools without building or hosting a separate MCP server. Existing authentication (JWT/API key), quotas, and logging continue to apply unchanged since MCP and REST traffic share one policy path.
This summary was generated automatically by AI from Google Developers's publication. It is our own text, not a copy of the original — facts, figures and quotes belong to the source, linked above and below.
What changed?
- 1API Gateway accepts MCP JSON-RPC requests and transcodes tools/call into REST requests on the same endpoint
- 2Requires OpenAPI 3.0.x or 3.1.x (2.0 not supported); annotate spec with x-google-api-management.mcp and x-google-mcp-tool
- 3tools/list discovery is unauthenticated by default but can be secured with JWT (API keys cannot secure discovery)
- 4tools/call always enforces the underlying REST operation's existing authentication
- 5ADK and other MCP clients can connect directly via the gateway's /mcp endpoint
- 6Public Preview limits: no support for HTTP 204 empty-body operations, deeply nested schemas may not render fully, max 1,000 tools per gateway, MCP and model routing cannot be enabled together
Why it matters
Many enterprise capabilities sit behind REST APIs that agents can't call directly; this removes the operational burden of standing up and maintaining a separate MCP server, making it faster to connect agents (voice, chat, automation) to existing backend systems like CRMs or order/status APIs.
What it means for AI agents and contact centers
Tenesys could use this to expose CRM, ticketing, or call-analytics REST endpoints directly as MCP tools for voice agents without extra infrastructure — worth testing latency, authentication behavior, and whether existing API policies (quotas, logging) hold up when called via MCP versus direct REST, especially for tool-calling in live call flows.
🧪 Worth Testing
Could simplify and speed up integrating existing backend/CRM REST APIs as callable tools for voice agents, reducing engineering overhead of maintaining separate MCP servers while reusing existing auth and quota infrastructure.
Sources
- Google DevelopersOfficialPrimary sourceOriginal article →24 Sept 2026, 03:00
- Published by source
- 24 Sept 2026, 03:00
- Found by our system
- 2 Oct 2026, 19:51
- Summary generated
- 2 Oct 2026, 19:54
This article was written by AI from the original source. Facts, numbers and prices come from the source; missing values are marked “Not specified”. Legal notice, copyright and privacy