Is my new prompt working better than the old one?

The honest answer to “is the new prompt better” is rarely obvious from spot-checking outputs. Better on what, for whom? A prompt can improve quality and quietly double cost, or fix one cohort and regress another.

Preserve the prompt or release identifier as a trace property. Then use Groups to compare the sessions that share it and inspect the related issues, users, outcomes, cost, and execution behavior.

Treat a before-and-after difference as evidence, not automatic proof of causality. Open the affected sessions and control for traffic mix, environment, and use case before calling one prompt better.