A new technical essay argues that prompt engineering fails quietly when prompts change, models update or surrounding product assumptions shift. The proposed answer is prompt regression: treating prompts like software artifacts that need tests.
The idea matters because many AI products rely on prompts that are difficult to inspect once embedded in workflows. A small wording change can alter behavior without throwing a conventional error.
For teams shipping AI features, regression testing can make prompt work more disciplined and reduce the risk that improvements in one case break another.