An online edition AI Agents, Engineered Designing, Building, Evaluating, and Operating Agents You Can Verify Start reading Search Preface 5 min · 1 figure I. Foundations 1 What Is an Agent? 16 min · 4 figures 2 The Engine: How Language Models Work 43 min · 6 figures II. Building Agents 3 The Agent Loop 🔒 4 Planning, Reasoning, and Self-Correction 🔒 5 Tools and the Action Space 🔒 6 Skills, Protocols, and Interoperability 🔒 III. Context Engineering 7 Managing the Context Window 🔒 8 Retrieval and Knowledge 🔒 9 Memory: Working State Across Long Runs 🔒 IV. Patterns and Choices 10 Workflows and Composition Patterns 🔒 11 Multi-Agent Systems 🔒 12 Oversight and Autonomy 🔒 13 Writing the Outer Loop 🔒 14 Choosing Your Approach: When Not to Build an Agent 🔒 V. Making Agents Reliable 15 Observability and Debugging 🔒 16 Evaluating Agents 🔒 17 Security, Safety, and Guardrails 🔒 18 Reliability, State, and the Harness 🔒 VI. Shipping and Operating 19 Cost, Latency, and Performance 🔒 20 Deploying and Scaling 🔒 VII. Applications and the Road Ahead 21 Coding Agents 🔒 22 The Coding Workflow in Practice 🔒 23 Research and Business Agents 🔒 24 Agent UX and Human Trust 🔒 25 Transversal Recipes: Big Patterns That Cut Across Industries 🔒 26 Agents as Classifiers and Scorers 🔒 27 The Frontier and How to Keep Learning 🔒 Appendices A A Minimal Agent, Annotated 🔒 B Glossary 22 min · 0 figures C Annotated Further Reading and Source Map 🔒