What is a judge hash
A judge hash is the cryptographic hash of the exact verification prompt (and the named judge model and version) under which a verification record was produced. Every verification record pins its judge by this hash.
Why it matters: the judge hash makes verification reproducible and correctable. If a blind spot is later found in judge version N, the hash defines an exact, queryable cohort of every record produced under it. The publisher re-verifies that cohort under the fixed judge, issues errata where scores materially change, and publishes the event. "Our verifier improved" becomes an auditable correction, not a quiet embarrassment.
Retired judge prompts are published in full against their hash (deferred publication), so every historical record is eventually reproducible from purely public materials.