principles.fyi · the brain · concept

prompt engineering

Carefully wording and structuring your prompt to get better answers.

Prompt engineering is the practice of designing the prompt — phrasing, formatting, adding examples, giving step-by-step instructions — so the model produces what you actually want, without changing any of its weights. It works because a decoder's output is conditioned entirely on its input tokens, so the prompt is the one lever you control at use-time. Common moves include few-shot examples, asking the model to reason step by step, and assigning a role. It complements, rather than replaces, the training-time tuning from Book 01 (fine-tuning, RLHF).