Amazon Bedrock AgentCore Gateway adds opt-in support for MCP 2026-07-28
AWS shipped same-day support for the stateless MCP revision in AgentCore Gateway: gateways advertise the protocol versions they speak, clients select a version per request, and existing 2025-era clients keep working unchanged.
On the day the 2026-07-28 revision went stable, AWS published support for it in Amazon Bedrock AgentCore Gateway, the managed front door that aggregates Lambda functions, APIs, and MCP servers behind a single MCP endpoint. Upgrading is opt-in: a gateway advertises the protocol versions it speaks through a single configuration field (an UpdateGateway call), and clients select a version on every request via the MCP-Protocol-Version header.
Per the announcement, a gateway serves each request in the requested version when it appears in supportedVersions, rejects unsupported versions with HTTP 400 and error code -32022 plus the supported list, and defaults requests that omit the header to 2025-03-26. Adding 2026-07-28 to a gateway that also advertises 2025-11-25 changes nothing for clients that keep requesting the older version.
The post frames the revision as the largest since MCP launched and notes the new governance guarantees (feature lifecycle policy, extensions framework) that are designed to limit future breakage. See the MCP 2026-07-28 revision record for what changed.
Related spec revisions
- MCP 2026-07-28 - current
How was this verified, and what are the sources?
Published · last verified · confidence 0.90.