The next Model Context Protocol specification, 2026-07-28 , is the largest revision since the protocol launched. The release candidate locked on May 21, 2026, and the final spec publishes on July 28. It contains breaking changes to transport, authorization, and how tool schemas are handled. A server that is correct against 2025-11-25 today is not broken. Nothing here is a present-tense vulnerability. But several of these changes are security properties, not just compatibility ones — reques...