Before you ship a prompt change, know what breaks.
Save the real inputs and outputs you keep re-checking by hand. Paste a baseline and a candidate output side by side, mark pass or fail, and get an explicit improved / same / regressed verdict per case — instead of another spreadsheet tab or scrollback search through old chats.
Save a case
Real input + what a good answer looks like.
Compare outputs
Paste baseline vs. candidate, mark pass/fail.
See the verdict
Improved, same, or regressed — saved to history.
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Illustration of the comparison workflow — not live data.
Built for the change you're about to make
Cases outlive the chat tab
Every input, expected behavior, and note is saved per project so the next prompt change starts from evidence, not memory.
No model connection required
Paste outputs from whatever you're using today. Mark each side pass or fail and the tool derives the verdict.
History you can return to
Every comparison run is kept per case, so you can see exactly when a case started failing.