Read a cohort trace

trace=summary exposes redacted lifecycle events such as planning, running, replanned, fallback and completed. Events contain identifiers, timestamps, revision, member/edge counts and aggregate reasons. They never contain prompt, completion, hidden-state bytes, dtype/shape payloads, memory addresses, peer addresses, keys or transport handles.

The JSON endpoint is cursor-paginated by event UUID. The SSE representation uses the same URL. Every timeline item retains the backwards-compatible cohort event; planning, running, replanned, fallback and completed items also emit the named cohort_planning, cohort_running, cohort_replanned, cohort_fallback and cohort_completed mirror with the same event identifier. Control events are connected, ping, complete or a sanitized error. Reconnect with the last event identifier and deduplicate generic/named mirrors by that identifier.

Terminal summaries include mode_used, members_used, fallback_used, fallback_reason, charged_credits, timestamps and revision. A missing field is unknown, not zero.