Events & transcripts

Every incremental and final event carries a stable turnId. UI must upsert in place by turnId — never append each delta as a new bubble.

session.on('asr_partial', ({ turnId, text }) => {
  upsert({ id: turnId, role: 'user', text, live: true });
});
session.on('asr_final', ({ turnId, text }) => {
  upsert({ id: turnId, role: 'user', text, live: false });
});
session.on('assistant_text_delta', ({ turnId, text }) => {
  upsert({ id: turnId, role: 'assistant', text, live: true });
});
session.on('assistant_text', ({ turnId, text }) => {
  upsert({ id: turnId, role: 'assistant', text, live: false });
});

Event map

Event	When	UI
statechange	State machine transition	Controls / indicators
asr_partial	Provisional ASR	Update user row + live cursor
asr_final	User turn confirmed	Replace provisional text
user_audio_end	VAD ends user speech	Latency start marker
assistant_text_delta	Model text fragment	Upsert assistant row (prefer accumulated text)
assistant_text	Reply confirmed	Commit final text
assistant_audio_start / _end	Playback bounds	First-audio latency, speaking state
turn	Turn committed	History
usage	Usage snapshot	Metrics
finished	Session ended	Teardown UI
error	Normalized error	Toast / retry

assistant_text_delta.delta is the new fragment; render accumulated text. Finals may normalize punctuation.

Payload shapes: VoiceSessionEventMap in the API reference.