A circuit breaker for AI agents is an automatic control that pauses an agent the moment a measured condition crosses a threshold (too many errors, too much spend, too many actions, too many retries) and then refuses to resume until a human re-authorizes it. It does not wait for a person to notice trouble and react. The threshold is always watching, even at 3 a.m. when no one is. When the breaker trips, the agent stops doing damage on its own, and restarting becomes a deliberate human decision rather than an automatic retry. That single property, firing by itself and resuming only on a human's say-so, is what separates a circuit breaker from every other stop.
This article covers what the circuit breaker pattern is, why agents need automatic thresholds instead of attentive humans, what to trip on, how resume semantics work, how the AI agent circuit breaker differs from a kill switch and a rate limit, and how it fits the LoopRails method (Grade · Guard · Show · Prove) described in the framework. It ends with a checklist.
What the circuit breaker pattern is
The circuit breaker is an old idea borrowed three times over. It starts in electrical engineering: a breaker trips and cuts the circuit when current exceeds a safe level, which keeps a wire from overheating. The defining move is that it acts on a measured threshold, automatically, with no person in the path.
