Barge-in
Barge-in is the voice-agent feature where the user can interrupt the assistant mid-response — the assistant detects the speech and stops talking — making conversations feel natural instead of robotic turn-taking.
By 2026 barge-in is non-negotiable for production voice agents. The user starts speaking; the agent's voice activity detector (VAD) detects it within ~50-100ms; TTS halts; STT begins on the user's interrupting speech. Cartesia, ElevenLabs, OpenAI Realtime, and others all expose barge-in primitives. Implementation gotchas: distinguish actual barge-in from background noise; handle partial agent speech (mid-sentence cut should leave the agent in a coherent state); resume gracefully if the interruption was brief. Voice agents without barge-in feel painfully like IVR.
When to use barge-in
- Realtime voice agents.
- Conversational interfaces.
Common mistakes
- Triggering barge-in on background noise — annoys the user.
- No graceful handling of mid-sentence interruption.
FAQ
What is barge-in?
Barge-in is the voice-agent feature where the user can interrupt the assistant mid-response — the assistant detects the speech and stops talking — making conversations feel natural instead of robotic turn-taking.
When should I use barge-in?
Realtime voice agents. Conversational interfaces.
What are the most common mistakes with barge-in?
Triggering barge-in on background noise — annoys the user. No graceful handling of mid-sentence interruption.
Related terms
- Voice (LLM apps) — Voice in LLM apps refers to the full speech pipeline — speech-to-text (STT), language model, text-to-speech (TTS) — that lets users converse with an AI assistant in spoken language.
- Streaming STT — Streaming STT (speech-to-text) emits partial transcriptions as the user speaks — instead of waiting for end-of-utterance — enabling sub-second response from a voice assistant.
- AI agent — An AI agent is a system where a language model autonomously plans and executes a sequence of tool calls to accomplish a goal.
Last updated: 2026-06-01. Raw markdown: https://promtable.com/glossary/barge-in.md.