Why AI Agent Retry Logic Is Really an Event-Driven Architecture Problem

Synchronous call chains in multi-service backends appear reliable during demos but break down under real production load, as tail latency compounds across each service hop. When one downstream service slows or fails, the entire chain stalls — even services that completed their work correctly are blocked. Introducing a message queue decouples services so each can process events independently, preventing one slow component from backpressuring the rest. However, queues introduce their own challenges: at-least-once delivery semantics, duplicate messages, ordering guarantees, and poison message handling. The author argues these same distributed-systems problems resurface in AI agent pipelines that execute sequential tool calls, making retry logic a queueing problem in disguise.