#Harness

Ten dollars buys twenty dollars of credit on Trae. I spent eighteen of it in one night, then found out Auto mode was routing to GPT-5.2 and Gemini Flash the whole time — and still shipped the work.

Everyone's arguing about which model tops the benchmarks. Nobody's talking about the thing that actually decides whether your agent works — the harness wrapped around it. Here's what's inside one, why it matters more than the model, and why you're already building them without knowing it.