Prompt patterns

A prompt that works twice is a prompt with four things in it: the role you want taken, the context that makes the task specific, the constraints that rule out the wrong answer, and the output format you actually need. Missing any one of them is why the same request produces something useful on Monday and something unusable on Thursday.

Constraints do more work than people expect. "Do not invent figures — if a number is not in the source, say so" removes an entire class of failure. So does naming the audience and the length. Write the prompt as though you were briefing a capable new colleague who cannot ask you a follow-up question, because functionally that is what is happening.