Short responses being ignored or the agent not detecting when you've stopped speaking is typically caused by the Voice Activity Detection (VAD) configuration in the multimodal OpenAI agent integration. Key factors include: • Minimum speech duration (

prefix_padding_ms

): If your utterance is shorter than this value, it may be ignored. • Silence duration (

silence_duration_ms

): The system waits for this amount of silence before ending a speech segment. If your pause is shorter, it may not register as the end of speech. • VAD sensitivity (

threshold

): If set too high, quieter or shorter utterances may not be detected as speech. There is also built-in logic to avoid processing utterances that are too short, which can cause very brief responses to be ignored entirely. To improve detection of short utterances, you can adjust these VAD parameters. For example:

turn_detection=openai.realtime.ServerVadOptions(
    threshold=0.4,  # Lower for more sensitivity
    prefix_padding_ms=100,  # Lower to detect shorter speech
    silence_duration_ms=300  # Lower to detect end of speech faster
)

Lowering these values can help with short responses, but may also increase the chance of false positives or interruptions. Adjust these settings to find the right balance for your use case. Sources: Voice activity detection (VAD) parameters | LiveKit Docs | livekit-agents/livekit/agents/voice/agent_activity.py | How does end-of-utterance detection work in conversations? | Improving voice AI's turn detection with transformers | Speech & Audio Processing | livekit/livekit_composite | DeepWiki