Segurança de IA, agentes e nuvem — em duas línguas.

There is a common criticism — “MCP has no authentication” — that used to be true and no longer is. The specification defines an authorization model. The problem shifted from “it does not exist” to “it exists and almost nobody implements it”, which is a different and more tractable problem. The model, in three obligations The June 2025 revision reclassified the MCP server as a pure OAuth resource server — it does not authenticate users, does not issue tokens, does not manage login. Three tasks remain: Answer 401 with a WWW-Authenticate header pointing at the protected resource metadata document. Publish that document per RFC 9728, naming which authorization server it trusts and which scopes exist. Reject every token not issued for it — audience validation. This is the only genuinely critical item and the one most often skipped. The client acts as an OAuth 2.1 client, with PKCE mandatory using S256, and discovers the authorization server through the metadata chain. Later revi...