Set the unique-event definition

Sets which fields split detections into separate events for the given scope. axes is any subset of source, detail, trace, machine, origin; an empty array keeps only the baseline (account, agent, sink); a name outside that list is ignored, not rejected. A product your account does not hold is a 400. OMITTING axes entirely clears this scope's row so it inherits the level below it; that is how you reset a machine to the account default. Applies to detections recorded from now on: it does not re-group what is already stored, and a field that was not keyed was never stored per-occurrence, so no later change can split history that has already merged. On success replies 204 No Content. Cookie callers must pass CSRF.

This is a write: a read-only API key is refused with 403.