Preface

The "Gang of Four" once gave object-oriented programming a shared vocabulary: instead of reinventing a solution each time, engineers began to name it — "Observer", "Strategy", "Factory".

Agentic programming today is where OOP was before the patterns catalog existed: the techniques are known, but they lack shared names, and the knowledge is scattered across articles, talks, and framework code. This book is an attempt to assemble such a catalog for agents and LLMs: to name recurring solutions and describe their forces and trade-offs.

Like any patterns catalog, it is first of all a compilation: most of the solutions were not invented by the author but gathered from existing sources — Anthropic's engineering guides, community practices, skill packs, articles, and talks; primary sources are cited in the chapters. To these are added the author's own findings and ideas, tested in his own practice.

The book is living and open. Patterns are added and refined; see CONTRIBUTING.