Your agent reports “done — all tests pass.” Do you believe it?

Nothing in that sentence is evidence, and the cost of finding out lands on you, later. I’ve been building with AI coding assistants for years, and the failure that kept costing me time was never that the model wrote bad code. It was that the model told me it was done, and I believed it. This post is the mechanism I built so I don’t have to — written out in enough detail that you can judge whether it would hold up against your own agent.

Ranex is a kernel — ordinary, inspectable code — that stays outside the AI’s loop and judges every step of its work. It never asks a model what to do next. Rules an agent can read are suggestions; rules compiled into code are constraints.

The problem is not that AI writes bad code

An AI writing software is a blindfolded dart thrower with a guide shouting coordinates. Two things go wrong, and they’re separate problems: