The effectiveness of TDD for coding agents predicts the effectiveness of simulative reasoning for all agents.
You know how when you think about what to do, you are running little simulations in your head? For many people this is unconscious, but folks with good metacognition observe it directly. We consider what will happen if you do x or y before we act – it’s an important part of decision making.
Your project’s test suite is how your coding agent does the same; It’s an environment for simulative reasoning. Every time it writes some code and runs a test, it’s simulating: What will happen at runtime if I do this? In a well setup project it simulates, reasons about results, and reattempts until it has something that works in the simulation. Then it knows what to do in the real world: what code to leave in for execution at runtime.
If you are working with coding agents, you have the benefit of experimenting with the most advanced agents in the world. *The lessons you learn there can be generalised for use with other agents.*
