Trace Anatomy: Reading an Agent Run Like a Professional

The trace is the only record you get of a run that will never repeat. Learn what a span carries, what to record on model calls, tool calls and decisions, where the OpenTelemetry GenAI conventions actually stand — then diagnose three traces that look fine and are not.

Content current as of 2026-09.

Lessons

1. The trace is the primary artifact
2. What to record on every span
3. OpenTelemetry GenAI conventions: what is standard, what is not
4. Three traces with something wrong
5. From traces to evals, cost, and forensics