DevFlow Conf 2027

A field report on running long-lived agents in production: timeouts, retries, poison inputs, and the runbook that finally made the pager quiet. We started with one agent that could file a support ticket and ended up with a fleet of them touching billing, inventory and customer email. Everything that broke, broke at night — a tool call that hung for nineteen minutes, a retry loop that re-sent the same refund four times, and a prompt change that quietly doubled token spend on the busiest queue of the week. This keynote walks through the three incidents that reshaped our architecture and the guardrails we shipped after each one: hard per-step deadlines, idempotency keys on every side effect, a spend ceiling enforced outside the model, and a replay view that lets an on-call engineer see exactly what the agent believed at the moment it went wrong. You will leave with the runbook we now hand to every team before their agent gets production credentials, the four dashboards we page on, and an honest account of which safeguards were worth the engineering time and which ones we deleted six weeks later.