I spent ten years building enterprise Java systems — a payments monolith broken into Spring Cloud microservices, banking applications, and currently a Cisco security platform. More recently I moved into building LLM systems seriously. The surprise wasn't how much I had to learn. It was how much transferred.
Agentic systems are distributed systems. The vocabulary is new; the failure modes are not.
Timeouts and retries — same problem, worse defaults
A Java service that calls a flaky dependency without timeouts is a junior-engineer mistake. An agent that calls an LLM without them is somehow normal. LLM calls are slow, occasionally hang, and fail in novel ways (malformed JSON, refusals, half-finished tool calls). Everything Resilience4j taught me applies directly: bounded retries with backoff, circuit breakers that fail fast with an honest error instead of silently substituting something expensive, and — this one is new — semantic failure detection, because an LLM can return HTTP 200 with garbage inside.
In Atlas, the gateway circuit-breaks to 503 + Retry-After when the model endpoint is down. That is deliberately boring. Boring is the point.
