OpenTelemetry Traces

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Where traces fit

Voice Metrics tells you which turn was slow and which stage dominated it, on every call and with no setup. A trace tells you what ran inside that stage: the model request, the streaming adapter, each tool call. Use it when the stage number does not explain the delay. An LLM stage that was really a slow tool call, or a TTS stage that was slow in the stream adapter rather than at the provider, look identical in a stage breakdown and obvious in a span tree.

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Reading the span tree

Tuner renders the trace against a time axis, with each bar positioned relative to the start of the session.

• Follow the widest bar at each level. Above, agent_turn is 4.84s and the tts_node under it is 4.62s, so synthesis dominated that turn, not the model.
• Siblings overlap. llm_node and tts_node both start at 00:00, because synthesis streams on the first tokens. Children do not sum to their parent, the same way the pipeline stages do not sum to TTFB.
• Collapse large traces. The call above has 171 spans. Collapse to the turn level, then expand the one turn you care about. Click a span to open its details. Span names come from your framework. See LiveKit traces or Pipecat traces.

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Turn on traces

Setup lives with your integration. A Traces tab appears on the call once spans have arrived and matched. Calls with no trace show no tab.

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What Tuner stores

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Next steps