Self-refine is a prompting pattern where the same LLM plays three roles in a loop: author (produces a draft), critic (reviews the draft and lists specific issues), reviser (rewrites the draft to address the critique). Each round of author + critic + reviser is one 'refine' step; the loop typically runs 1-3 rounds before terminating. The technique improves quality on tasks where a critique then revise pattern is a natural fit (writing, code, structured arguments) and adds little on tasks the first draft already nails. Cost is roughly 3x a one-shot prompt per round.