What Is Harness Engineering? A Builder's Guide

Key Takeaways Harness engineering is designing the environment, constraints, and feedback loops that make AI coding agents reliable The core formula: Agent = Model + Harness — the model is just one piece of the system Three regulation types: maintainability, architecture fitness, and behavior LangChain improved agent accuracy from 52.8% to 66.5% by changing only the harness — same model A solid harness includes context files, static analysis, automated tests, reusable skills, and living document