THE THREE DISCIPLINES AROUND THE MODEL

CHAPTER SUMMARY Prompt engineering shapes the wording of a single interaction. Context engineering curates everything placed in the context window across turns. Harness engineering designs the whole system outside the model, including code that enforces limits the model cannot enforce on itself. The three nest together, with prompts inside context and context inside the harness. Above a basic level of model ability, the harness often explains much of the difference in real-world reliability. KEY TERMS REVIEW Prompt engineering: crafting the instructions for a single interaction. Few-shot prompting: including a small number of examples in the prompt. Context engineering: curating all information placed in the context window across turns. Harness engineering: designing everything outside the model so an agent runs reliably. System prompt: the standing instructions given to the model, managed by the harness. Shell command: a typed instruction given to a computer's operating system.