Tempo's metrics-generator defaults the exemplar label to traceID, which the Prometheus datasource's exemplarTraceIdDestinations (trace_id) never matched: exemplars rendered in Grafana but didn't link to Tempo. Set trace_id_label_name in the overrides so trace_id is the one correlation key everywhere. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>