Observability

Every agent session produces a structured trace at workdir/<session_id>/trace.jsonl, written directly by the runtime regardless of whether any hooks are declared. When murmur-hook-eval is configured with at least one scorer, that hook (not the runtime) additionally writes workdir/<session_id>/eval.jsonl at session end. See Session trace (trace.jsonl) and Structured evaluation (eval.jsonl) for the full schemas, and mur trace / mur eval for how to read them.