The Prompt Pattern Library — 40 Reusable Patterns

A reference catalogue (patterns.md) of 40 named, reusable prompt-engineering patterns organized into 11 categories: role and persona framing, output-format control, verification and self-critique, decomposition, constraint-stacking, few-shot selection strategies, comparison and critique patterns, iterative-refinement patterns, ambiguity-resolution patterns, context-window management, and tone/register control. Every pattern entry follows the same seven-part shape — category, purpose, when to use it and when not to, a fill-in-the-blanks template, a worked example, a before/after comparison, and known limitations — and is written to be looked up individually rather than read in order. The README is a problem-first index: match your actual situation ('reduce hallucinated facts,' 'get output your code can parse the same way every time') to the pattern that addresses it, plus a short list of which patterns are designed to be paired together. Intended as a lookup reference for anyone writing prompts regularly who wants a named vocabulary of techniques rather than reinventing the same fix each time; all 40 patterns and examples are original.