What is a Circuit Breaker for AI Agents?
An automated safety mechanism that halts an agent's tool calls when anomalous patterns are detected — call rate spikes, repeated denied calls, or error rate acceleration. Triggers automatically, unlike manual kill switches.
WHY IT MATTERS
From electrical engineering: when current exceeds safe levels, the breaker trips. For AI agents: when tool call patterns exceed safe thresholds, the breaker trips and all calls are denied until the situation is resolved.
Circuit breakers detect patterns that individual call policies miss. 100 legitimate read_file calls per minute might not violate any per-call policy, but the velocity is anomalous and warrants investigation.
After tripping: auto-reset (the breaker reopens after a cooldown period) or manual reset (requires operator intervention for severe triggers). The choice depends on the risk level.
HOW POLICYLAYER USES THIS
PolicyLayer implements circuit breaker patterns through YAML rate-limiting policies. When tool call rates exceed defined thresholds, PolicyLayer automatically denies all subsequent calls until the rate drops below the threshold. Configure per-tool breakers (e.g., halt write_file at 50 calls/minute) or global breakers (halt all tools at 200 calls/minute).