Observability

The cheap part of a failed agent run is running it again. The expensive part is that you can’t — the failure was non-deterministic, so the run that broke is gone, and you pay to summon it back. A cost model shows why reproduction, not repair, dominates your debugging bill, and why always-on tracing is almost always cheaper than the alternative it replaces.

Most agent failures don’t throw. The run returns a result, exit code zero, and the result is wrong — or it burns an hour and quietly gives up. If your monitoring only counts exceptions, you’re blind to the failures that actually cost you. A taxonomy of agent failure modes and the specific instrumentation that catches each one before your users or your bill do.