Mutation path is not one ARTF documents
The path is rooted and well formed but is not one of the semantic references ARTF v1.0 documents, so only a prior agreement can resolve it.
What it means
The path does not match /user/data/segment, /imp/{imp id}, /imp/{imp id}/pmp/deals/{deal id}, or /seatbid/{seat}/bid/{bid id}. Those four are what the specification and its example docs actually show.
Why it matters
Paths are deliberately semantic, so the vocabulary can grow, and an orchestrator may well have agreed a private one with a given agent. It stays a warning for that reason. What it cannot do is resolve against the auction, so nothing further about this mutation is checked.
How to fix it
Use a documented path where one fits. If the path is a private arrangement, expect any generic tooling in the chain to treat it as opaque.
Example that trips it
{ "intent": "ACTIVATE_DEALS", "op": "OPERATION_ADD", "path": "/curation/pods/pod-1", "ids": { "id": ["deal-2"] } }Check your payload
Paste a bid request or response into the tester to see whether this code fires against it, or gate on the id in CI with the CLI: the id is stable, wording is not.
Back to the full diagnostic code reference.