AI agent glossary
Circuit breaker
A reliability pattern that stops calling a failing service for a while after repeated errors, and switches to a fallback instead of retrying endlessly.
When a model API or tool starts failing, naive retries make things worse: every run keeps hammering the broken service, queues back up, and the retries themselves add load. A circuit breaker watches the error rate and, once it crosses a threshold, opens the circuit, so calls fail fast or go to a fallback.
After a cooling-off period it lets a few test calls through. If they succeed, normal traffic resumes; if not, it stays open.
For agents, the fallback might be a different model or provider, a cached answer, a simpler degraded mode, or a clear message that the task will be retried later. Pair circuit breakers with retries in a single layer and with timeouts at every level.
After ten consecutive overload errors from the primary model, the breaker opens and routes new agent steps to a fallback model for one minute before testing the primary again.
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