Provenance
Who asserted a thing, when, on what basis, and how it can be checked — recorded on the object itself.
Provenance is a property of every object in the world, not a policy layered over some of them. It is what allows trust to compose: a credential is only as strong as the evidence beneath it, and the strength travels with it.
Machine-generated content is marked as machine-generated at the point of creation, at the object level. The question of whether a person wrote something is answered in the record rather than guessed at by a detector.
A system with provenance can still be wrong. It cannot be quietly wrong.