Update assistant

idintegerrequired

The unique identifier of the assistant to update

namestring

The name of the assistant (max 255 characters)

voice_idinteger

The voice ID to use for the assistant. Use the Get Voices endpoint with the mode parameter to get compatible voices for your engine mode.

language_idinteger

The language ID for the assistant. Use the Get Languages endpoint to get available languages.

typestring

The assistant type. Options: inbound, outbound

modestring

The engine mode. Options: pipeline, multimodal, dualplex

Changing the mode will reset mode-specific settings to defaults for the new mode.

timezonestring

The timezone for the assistant (e.g., "Europe/Bucharest", "America/New_York")

initial_messagestring

The initial message the assistant will speak when the call starts (max 200 characters)

system_promptstring

The system prompt that defines the assistant's behavior and personality

llm_model_idinteger

The LLM model ID to use. Only applies to pipeline mode.

Use the Get Models endpoint to get available models.

multimodal_model_idinteger

The multimodal model ID. Only applies to multimodal and dualplex modes.

Use the Get Models endpoint to get available multimodal models.

chat_llm_fallback_idinteger

Fallback LLM model ID for tool calls in multimodal/dualplex modes. Set to null to remove.

turn_detection_thresholdnumber

Turn detection sensitivity for multimodal/dualplex modes (0-1). Set to null for auto.

secondary_language_idsinteger[]

Array of additional language IDs the assistant can speak. Replaces existing secondary languages. Pass an empty array [] to remove all secondary languages.

"secondary_language_ids": [2, 3, 4]

knowledgebase_idinteger

The knowledgebase ID to attach. Set to null to remove knowledgebase.

knowledgebase_modestring

How to use the knowledgebase. Options:

• function_call - AI calls a function to search (required for multimodal/dualplex)
• prompt - Knowledge is injected into prompt (pipeline only)

folder_idinteger

ID of a folder to move this assistant into. Must belong to your account. Set to null to make it uncategorized. Omit to leave the folder unchanged.

label_idsinteger[]

Array of label IDs for this assistant. Each label must belong to your account. When provided, this replaces the assistant's current labels. Omit to leave labels unchanged; send [] to remove all labels.

"label_ids": [3, 5]

phone_number_idinteger

The ID of a phone number to assign. Set to null to unassign. Must belong to your account.

For `inbound` assistants, the phone number cannot be a Caller ID type and cannot be already assigned to another inbound assistant.

tool_idsinteger[]

Array of custom mid-call tool IDs to sync. Replaces all existing tool assignments. Pass an empty array [] to remove all tools. Each tool must belong to your account.

"tool_ids": [1, 5, 12]

toolsarray

Array of built-in tools. Replaces all existing built-in tools. Pass an empty array [] to remove all tools.

**call_transfer** - Transfer the call to another phone number
- `phone_number` (required): Phone number to transfer to
- `description`: When to transfer the call
- `custom`: If true, AI can determine transfer number dynamically
- `timezone`: Timezone for transfer availability
- `warm_transfer`: Send a message to the customer before transferring (default: `false`)
- `warm_transfer_message`: Prompt telling the AI what to say before transferring (e.g., "Tell the customer that the call is being transferred.")

**warm_call_transfer** - Warm transfer with supervisor briefing
- `supervisor_phone` (required): Phone number to dial for the warm transfer (e.g., "+14155552001"). If `custom_sip` is enabled, this is a SIP address or internal extension instead.
- `outbound_phone_id` (required): ID of the phone number used to dial the supervisor.
- `description` (required): **When to transfer** — describes when the AI should initiate the warm transfer (e.g., "Transfer the call to a human supervisor when the customer requests to speak with a real person.")
- `custom_sip`: Enable to enter a custom SIP address or internal extension instead of a phone number (default: `false`)
- `caller_id_mode`: What phone number the supervisor sees when receiving the call. Options: `outbound_number` (default — shows the outbound phone number), `customer_number` (shows the caller's number), `custom` (shows a custom number)
- `custom_caller_id`: Custom phone number shown to supervisor. Only used when `caller_id_mode` is `custom`.
- `hold_music`: Audio played to the caller while on hold. Options: `hold_music` (default — plays default hold music), `none` (silence, no music)
- `hold_music_volume`: Volume level for hold music, 0-100 (default: `80`)
- `hold_message`: Message spoken to caller before placing them on hold (default: "Please hold while I connect you with a supervisor.")
- `summary_instructions`: Instructions for how the AI should brief the supervisor about the call (default: "Introduce the conversation from your perspective:\n- WHO is calling (name, company if mentioned)\n- WHY they called (their goal or problem)\n- WHY a human is needed at this point\n\nKeep it brief (2-3 sentences).")
- `briefing_initial_message`: The first message the AI says to the supervisor when they answer (default: "Hello! I have a caller on the line who needs your assistance. May I brief you on the situation?")
- `connected_message`: Message spoken to caller after supervisor is connected (default: "You are now connected with a supervisor. I'll leave you to it.")

**end_call** - End the call programmatically
- `description`: When the AI should end the call

**dtmf_input** - Send DTMF tones (keypad input)
- `description`: When to use DTMF input (for IVR navigation)

**collect_keypad** - Collect keypad input from the caller
- `timeout`: Seconds to wait for input, 1-30 (default: 5)
- `stop_key`: Key that ends input. Options: `#` (default), `*`

**calendar_integration** - Schedule appointments via Cal.com or Calendly
- `calendar_type`: Calendar provider. Options: `calcom` (default), `calendly`
- `description`: When to offer scheduling

Cal.com fields (`calendar_type: "calcom"`):
- `calcom_api_key` (required): Your Cal.com API key
- `calcom_event_slug` (required): The event type slug from Cal.com
- `calcom_team_slug`: Team slug if the event belongs to a Cal.com team
- `calcom_endpoint`: Cal.com API region. Options: `us` (default — `https://api.cal.com`), `eu` (`https://api.cal.eu`), `custom` (uses `calcom_custom_endpoint`)
- `calcom_custom_endpoint`: Custom Cal.com API base URL. Only used when `calcom_endpoint` is `custom` (e.g., `https://my-calcom-instance.com`).
- `calcom_event_id`: Cal.com event type ID. When provided, the event name is resolved from Cal.com automatically.
- `calcom_event_name`: Human-readable event name (e.g., `"30 Minute Meeting (30 min)"`). Resolved from Cal.com when `calcom_event_id` is provided, or set explicitly.
- `calcom_booking_fields`: Array of custom booking fields for the event. Each field has:
  - `slug` (required): Field identifier
  - `type` (required): Field type (e.g., "text", "email", "phone", "select")
  - `label` (required): Display label
  - `required`: Whether the field is required (default: `false`)
  - `options`: Array of options for select fields

Calendly fields (`calendar_type: "calendly"`):
- `calendly_api_key` (required): Your Calendly Personal Access Token (PAT). Generate one from your Calendly account: **Integrations & apps → API & webhooks → Generate new token**.
- `calendly_event_type_uri` (required): Full Calendly event type URI (e.g., `"https://api.calendly.com/event_types/{uuid}"`). Must belong to the authenticated PAT's account.

**assistant_transfer** - Hand off the conversation to a different AI assistant mid-call (swaps voice, LLM, and STT to the target assistant)
- `assistant_id` (required): ID of the target assistant. Must belong to your account and cannot be the assistant being updated (no self-transfer).
- `description`: When to transfer (max 500 chars, default: "Transfer the conversation to this assistant when appropriate.")
- `message_before_transfer`: Optional message the AI speaks before switching to the target assistant (max 500 chars).
- `speak_transfer_greeting`: If `true`, the target assistant speaks its configured initial message after the transfer completes (default: `true`).

"tools": [
  {
    "type": "dtmf_input",
    "description": "Navigate IVR when needed"
  },
  {
    "type": "warm_call_transfer",
    "supervisor_phone": "+1234567890",
    "outbound_phone_id": 7,
    "description": "Transfer the call to a human supervisor when the customer requests to speak with a real person.",
    "custom_sip": false,
    "caller_id_mode": "outbound_number",
    "hold_music": "hold_music",
    "hold_music_volume": 80,
    "hold_message": "Please hold while I connect you with a supervisor.",
    "summary_instructions": "Introduce the conversation from your perspective:\n- WHO is calling (name, company if mentioned)\n- WHY they called (their goal or problem)\n- WHY a human is needed at this point\n\nKeep it brief (2-3 sentences).",
    "briefing_initial_message": "Hello! I have a caller on the line who needs your assistance. May I brief you on the situation?",
    "connected_message": "You are now connected with a supervisor. I'll leave you to it."
  },
  {
    "type": "collect_keypad",
    "timeout": 5,
    "stop_key": "#"
  },
  {
    "type": "assistant_transfer",
    "assistant_id": 14765,
    "description": "Transfer to the Support Assistant when the customer needs technical help.",
    "message_before_transfer": "Sure — let me transfer you to our support specialist.",
    "speak_transfer_greeting": true
  },
  {
    "type": "end_call",
    "description": "End call when done"
  }
]

tts_emotion_enabledboolean

Whether to enable emotional text-to-speech synthesis

voice_stabilitynumber

Voice stability setting (0-1). Higher = more consistent voice

voice_similaritynumber

Voice similarity setting (0-1). Higher = closer to original voice

speech_speednumber

Speech speed multiplier (0.7-1.2)

llm_temperaturenumber

LLM temperature setting (0-1). Lower = more deterministic

synthesizer_provider_idinteger

Custom TTS provider ID. Set to null to use language default. Use the Get Synthesizer Providers endpoint to discover available providers.

transcriber_provider_idinteger

Custom STT provider ID. Pipeline mode only. Set to null to use language default. Use the Get Transcriber Providers endpoint to discover available providers.

allow_interruptionsboolean

Whether to allow caller interruptions.

fillersboolean

Whether to use filler audio during processing.

filler_configobject

Custom filler word profiles per category. Replaces existing filler config. Each category is an array of short phrases.

• positive: Filler words for positive/affirmative responses
• negative: Filler words for negative/neutral responses
• question: Filler words when processing a question
• neutral: Filler words for neutral acknowledgments

"filler_config": {
  "positive": ["Great!", "Perfect!"],
  "negative": ["Hmm.", "I see."],
  "question": ["Good question.", "Let me check."],
  "neutral": ["Ok.", "Noted."]
}

recordboolean

Whether to record the call

enable_noise_cancellationboolean

Whether to enable noise cancellation

wait_for_customerboolean

If true, the assistant waits for the customer to speak first

max_durationinteger

Maximum call duration in seconds (20-1200)

max_silence_durationinteger

Maximum silence duration before re-engagement in seconds (1-360)

max_initial_silence_durationinteger

Maximum silence at call start before ending (1-120 seconds). Set to null to disable.

ringing_timeinteger

Maximum ringing time before giving up (1-60 seconds)

reengagement_intervalinteger

Re-engagement interval in seconds (7-600)

reengagement_promptstring

Custom prompt for re-engagement messages (max 1000 characters). Set to null to use default.

end_call_on_voicemailboolean

Whether to end call when voicemail is detected

voice_mail_messagestring

Message to leave on voicemail before hanging up (max 1000 characters). Set to null to disable.

endpoint_typestring

Voice activity detection type. Options: vad, ai

endpoint_sensitivitynumber

Endpoint sensitivity level (0-5)

interrupt_sensitivitynumber

Interrupt sensitivity level (0-5)

min_interrupt_wordsinteger

Minimum words before interruption is allowed (0-10). Set to null to disable.

ambient_soundstring

Background ambient sound. Options: off, office, city, forest, crowded_room, cafe, nature

ambient_sound_volumenumber

Ambient sound volume level (0-1)

is_webhook_activeboolean

Whether webhook notifications are enabled

webhook_urlstring

The webhook URL for post-call notifications. Set to null to remove.

send_webhook_only_on_completedboolean

Whether to send webhooks only on completed calls (not failed/no-answer)

include_recording_in_webhookboolean

Whether to include recording URL in webhook payload

post_call_evaluationboolean

Whether to enable AI post-call evaluation

post_call_schemaarray

Schema definition for post-call data extraction. Replaces existing schema.

  Field name (3-16 chars, lowercase, alphanumeric and underscores only)

  Data type. Options: `string`, `number`, `bool`

  Description of what this field represents (3-255 characters)

variablesobject

Key-value pairs of custom variables. Replaces all existing variables.

"variables": {
  "company_name": "Acme Corp",
  "product": "Premium Widget"
}

conversation_inactivity_timeoutinteger

Minutes of chat inactivity before the conversation is considered ended (1-1440). Set to null to disable. Default: 30

conversation_ended_retriggerboolean

Whether to allow re-triggering the conversation after it ends due to inactivity

conversation_ended_webhook_urlstring

Webhook URL called when a chat conversation ends due to inactivity. Set to null to remove. Separate from the main call webhook.

messagestring

Success message confirming assistant update

dataobject

  The unique identifier of the updated assistant

  The name of the assistant

  The current status of the assistant

  The type (`inbound` or `outbound`)

  The engine mode (`pipeline`, `multimodal`, or `dualplex`)