Two failure modes break unattended pipelines, and neither looks like an error. Silent failure: exits 0, produced nothing. False failure: the work finished, then cleanup crashed and it reported failure. ProveDone runs your command, then checks the artifacts on disk - existence, size, count, freshness, and whether this run actually created them. That last one is what everyone gets wrong. A stale artifact passes every naive "does the file exist" check ever written. No dependencies. Node 18+. MIT.