Prompt engineering

The same model gives a mediocre or an excellent answer, depending on how you phrase the question. Prompt engineering is the craft of getting that instruction right: stating the task, the context, the desired format and the boundaries clearly. Providing good examples often helps more than a longer explanation.

In a serious application the prompt is not a loose sentence, but a deliberate piece that is tested and version-controlled. If you change it, you measure with evals whether it gets better or worse, because a small rephrasing can make an unexpectedly large difference.

Prompt engineering is the cheapest dial to turn: you often solve a problem with a better instruction before you reach for RAG or fine-tuning.