Updating Configuration Mid-Stream

{
  "type": "UpdateConfiguration",
  "keyterms_prompt": ["account number", "routing number"],
  "max_turn_silence": 5000
}

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Supported fields

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Mode

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Turn detection

• min_turn_silence — Minimum silence in ms before an end-of-turn check fires. Lower values produce faster turn endings; higher values reduce entity splitting on numbers and proper nouns.
• max_turn_silence — Maximum silence in ms before forcing a turn to end, regardless of confidence. Increase for moments where you expect a longer pause (caller reading out a number, address, etc.).
• end_of_turn_confidence_threshold — Confidence threshold for ending a turn on Universal Streaming.
• interruption_delay — How quickly the first partial is emitted on U3 Pro. Lower values produce faster TTFT for aggressive barge-in; higher values produce more confident first partials. See Tuning early partial timing.

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VAD

• vad_threshold — Confidence threshold for classifying audio frames as speech. Increase for noisy environments to reduce false speech detection.

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Prompting and context

• prompt — Update the contextual prompt mid-stream as your application learns more about the conversation. See Prompting guide.
• keyterms_prompt — Replace the current keyterms list. The most effective way to improve recognition accuracy mid-stream — dynamically swap the list as your voice agent moves between conversation stages. See Keyterms prompting.
• agent_context — Pass your voice agent’s most recent spoken reply so the model has it as context for the next user turn. See Context carryover.
• language_codes — Update the set of languages transcription is steered toward; takes effect from the next turn. Pass an empty list to clear steering and return to native code-switching.

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Partials

• continuous_partials — Toggle steady-cadence partial emission on or off mid-session.

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Example

websocket.send(json.dumps({
    "type": "UpdateConfiguration",
    "keyterms_prompt": ["Kelly Byrne-Donoghue", "date of birth", "January", "February"],
}))

client.update_configuration(
    keyterms_prompt=["Kelly Byrne-Donoghue", "date of birth", "January", "February"],
)

ws.send(JSON.stringify({
  type: "UpdateConfiguration",
  keyterms_prompt: ["Kelly Byrne-Donoghue", "date of birth", "January", "February"],
}));

transcriber.updateConfiguration({
  keytermsPrompt: ["Kelly Byrne-Donoghue", "date of birth", "January", "February"],
});

​

Behavior notes

• UpdateConfiguration is a delta. Fields you omit keep their current values.
• mode, prompt, agent_context, interruption_delay, and continuous_partials are U3 Pro only.