Interruptions

With barge_in: true, the caller can interrupt the agent mid-sentence. The hard part is that people constantly make small sounds while listening, like "yeah", "mhm" and "right". An agent that stops for each one is unusable.

turns:
  barge_in: true
  barge_in_detector: maai # vad | backchannel-detector | maai
  interrupt_after: 300 # ms of speech before vad counts it (vad only)

DetectorsCopy Anchor Link

The detector emits either user_backchannel (keep talking) or interrupt. The policy waits hold_ms (200 ms by default) after an interrupt before stopping, and cancels the stop if a user_backchannel arrives in that window.

What happens when the agent stopsCopy Anchor Link

1. LLM generation and TTS are cancelled mid-stream.
2. The server emits agent.interrupted. Over the Realtime API, clients get input_audio_buffer.speech_started, and the response ends with status cancelled.
3. Clients must drop audio they haven't played. Buffered audio would keep talking over the caller.
4. If the reply was cut off before any audio played, it is dropped from the history, and the caller's words carry into their next turn. Otherwise the partial reply stays in the history, and any unanswered tool calls are marked interrupted.

TuningCopy Anchor Link

• Stops too often: use maai or backchannel-detector instead of vad, or raise interrupt_after (vad).
• Stops too slowly: lower hold_ms in a custom policy: StandardTurnTaking(hold_ms=100). See Custom turn-taking.
• Never interrupt (an IVR prompt, a legal disclosure): set barge_in: false, or filter STOP decisions in a custom policy (example in Custom turn-taking).

In the dashboard, barge-in rate and interruptions per call show how often callers cut in. Listen to a few with the call player to check the stops were real.