Google API Gateway previews MCP support
Google Cloud API Gateway can now expose existing REST operations as MCP tools in public preview. The feature uses a gateway’s OpenAPI definition and policy path instead of requiring a separately operated MCP server.
Existing API controls carry into tool calls
The Google technical announcement describes translating MCP requests into REST calls and returning the response. Authentication, quotas and logging follow the existing gateway configuration, with MCP and REST traffic using the same policy path.
API controls become tool boundaries
- OpenAPI contract
- Version 3.0 or 3.1; not 2.0
- MCP request
- Existing gateway authentication
- REST backend
- Same quotas and logging policy
- Returned response
- Preview; operation needs a backend
View data
| Evidence | Meaning |
|---|---|
| OpenAPI contract | Version 3.0 or 3.1; not 2.0 |
| MCP request | Existing gateway authentication |
| REST backend | Same quotas and logging policy |
| Returned response | Preview; operation needs a backend |
Google · published 2026-09-24. Source-bound illustration, not a performance benchmark.
Download imageThe preview requires OpenAPI 3.0 or 3.1; OpenAPI 2.0 is not supported. Developers opt in through the specification and can customize or skip individual operations. Exposed operations need a backend and a useful description. These prerequisites make the API contract part of the agent’s tool design.
Original sources
- Google: original announcementdevelopers.googleblog.com
Checked 9 Oct 2026 · A manually curated edition. Availability may change; company performance claims are not Trion test results. Editorial method.