Generated AI image by Google Gemini Nano Banana
Introduction
You’ve learned to write better prompts. You’ve learned to structure context. Now it’s time to think about what turns a model into an agent — and what keeps that agent under control once it’s running.
What Is Harness Engineering?
In my previous article, I mentioned context engineering quite a bit and how it’s important for developers to master in this AI era we’re in. If you’ve spent time on context engineering, you already understand one truth: the quality of what you give an AI model matters as much as the model itself.
Harness engineering is the discipline that comes next — and it’s a bigger shift than it first sounds.
Context engineering answers what do I put in the prompt? Harness engineering answers a different question: how does the model actually act — calling tools, tracking state across steps, staying inside guardrails — and how do I control that?