# Prompt Engineering ## What is Prompt Engineering Writing clear instructions to guide an AI model to produce the desired response. ## Best practices See [[Prompt Engineering Best Practices]] ## Strategies See [[Prompt Engineering Strategies]] ## Prompting current models Anthropic now publishes a general prompting guide plus one page per model, because the same instruction can help one model and hurt the next. Read the page for the model you use first: my notes on [[Claude Fable 5.2]] and [[Claude Opus 5.5]] summarize theirs. The main changes for current Claude models are in [[Prompt Engineering Best Practices]]: give the reason behind each rule, replace prefilled responses (they now return an error), control thinking with effort instead of token budgets, and tone down caps-lock tool instructions that make recent models overtrigger. ## Concepts ### Tokens Common sequence of characters found in text Tokenization -> Token Ization ### Temperature The higher the "temperature", the more variable/creative the responses ### Top p (OpenAPI) Controls diversity. 0.5 means it's considered half the "pool" of available words ### Presence penalty Controls the likelihood of talking about new topics ### Frequence penalty Controls the likelihood of repeating the same line verbatim ### Effort On current Claude models, the `effort` parameter replaces thinking budgets: higher effort means more thinking, and the model decides when to think (adaptive thinking). On some models (Opus 5, Fable 5.2), it barely changes the length of the reply, so ask for length in the prompt. See [[Claude Code effort levels]]. ## References - Anthropic, "Prompting best practices", Claude Platform docs: https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices ## Related - [[Chain-of-Thought (CoT) prompting]] - [[Claude Code effort levels]] - [[Claude Fable 5.2]] - [[Claude Opus 5.5]] - [[Context Engineering]] - [[Harness Engineering]] - [[Intent Engineering]] - [[Prompt Chaining]] - [[Prompt Engineering Best Practices]] - [[Prompt Engineering Strategies]] - [[Promptfoo]]