Sovereign AI Stack This document describes the Prove-Transform-Verify (PTV) protocol for hardware-anchored attestation of AI agent identity. PTV enables an agent to prove, at exercise time, that it is bound to an enrolled attestation key and an authorized configuration, without exposing model weights or inference inputs. PTV is a thin request/response profile over the RATS architecture (RFC 9334) and the Entity Attestation Token (RFC 9711). It does not replace workload identifiers such as SPIFFE or WIMSE. It does not attest behavioral continuity; behavioral continuity is a separate requirement class that relying parties need to treat as such. This revision is intended as Experimental. It defines a common CBOR/ CDDL message set, four message types, a COSE-based message protection rule, an informative EAT claim mapping, and a threat model that separates identity binding integrity from behavioral continuity.