MCP's Auth Hardening: What the Six New OAuth SEPs Fix, and What They Still Don't
In short, the MCP 2026-07-28 release candidate is getting attention for going stateless. The quieter story is a package of six SEPs that harden the protocol’s OAuth layer: issuer validation, credential binding, client type declaration, and cleanups around refresh tokens, scopes, and discovery. All six are worth shipping, and all six fix real failure modes. But they harden how a client authenticates to a server, and that was never the whole problem.