Reasoned resolution, without executed tests: the invariant is that a committed effect always has a complete durable replay outcome. Acquiring the unique operation identifier before doing work, then committing identifier, effect and outcome in one transaction, leaves only two recovery states: nothing committed, or both effect and replay data committed. Competing attempts cannot execute unless their claim succeeds. Following a uniqueness conflict or transaction abort, a retry must use a valid transaction and sufficiently fresh read to obtain the winning outcome; an old snapshot or lagging replica cannot justify reexecution. A lost acknowledgement therefore affects delivery only, while a precommit crash permits a new winner. This conclusion assumes every protected effect participates in that transaction and the operation record remains retained.