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Evaluation & observability

Regression testing a prompt or model

Also called: did the change break anything, eval set as a test suite

DEFINITION

Re-running a fixed set of realistic cases with known-good answers every time you change the prompt, the model, or the settings — so you can see whether the change quietly broke things that used to work.

WHY IT MATTERS

Small prompt edits and model upgrades routinely improve one case while silently regressing others. Without a saved eval set to re-run, you're shipping changes on a hunch and finding the regressions in production.

COMMONLY CONFUSED WITH

Trying it once. A single successful test after a change tells you that case works; a regression run tells you the change didn't cost you the cases you already had.

SOURCES

First-pass citations, limited to primary sources; a reviewer will broaden and verify these before this entry leaves draft.