# Barge-in

URL: https://docs.bithuman.ai/build/barge-in

> Let users talk over the avatar and stop it mid-sentence.

Talk over the avatar and it stops mid-sentence, then listens: that is barge-in.

- **The CLI and the Python agent:** the voice model's turn detection hears you start talking and cancels its reply; LiveKit Agents then clears the avatar's buffered audio and frames, so the mouth stops with the voice. In the Python agent it is `interrupt_response=True` on the turn detection, shown in [Voice agent in Python](https://docs.bithuman.ai/build/voice-agent/python#with-python).
- **Your own loop in Python:** when your speech detection fires, call `interrupt()` on the runtime and clear any reply audio you still hold. `run()` carries on with idle frames. With OpenAI Realtime, the event to watch is `input_audio_buffer.speech_started`:

```python
# excerpt: barge-in, in the event loop of conversation.py
elif event.type == "input_audio_buffer.speech_started":
    # the user started talking: drop the rest of the reply
    runtime.interrupt()
```

- **On the device:** `interrupt()` in Swift and Flutter; `resetState(true)` for Expression 2 and `resetAudio()` for Essence 2 on Android ([Companion app](https://docs.bithuman.ai/build/companion-app#let-the-user-interrupt)).
- **Pipecat:** `BitHumanVideoService` handles `InterruptionFrame`: the avatar drops the reply in flight and goes back to idle ([Pipecat](https://docs.bithuman.ai/platforms/pipecat/app#integrate-into-your-app)).
- **A cloud avatar without the plugin:** perform the RPC `lk.clear_buffer` on the avatar ([Cloud avatar](https://docs.bithuman.ai/platforms/livekit/cloud-avatar)).

Barge-in does not change billing: a session bills active session time, talking or idle, to the second.