> ## Documentation Index
> Fetch the complete documentation index at: https://docs.famulor.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Assistant

> Update the configuration of an existing AI assistant

This endpoint allows you to update the configuration of an existing AI assistant. All fields are optional – only the fields provided will be updated. For detailed field descriptions and options, see [Create Assistant](/en/api-reference/assistants/create).

### Path Parameter

<ParamField path="id" type="integer" required>
  The unique identifier of the assistant to be updated
</ParamField>

### Request Body

#### Core Fields

<ParamField body="name" type="string">
  The name of the assistant (max. 255 characters)
</ParamField>

<ParamField body="voice_id" type="integer">
  The voice ID to be used for the assistant. Use the [Get Voices](/en/api-reference/assistants/voices) endpoint with the `mode` parameter to get voices compatible with your engine mode.
</ParamField>

<ParamField body="language_id" type="integer">
  The language ID for the assistant. Use the [Get Languages](/en/api-reference/assistants/languages) endpoint to retrieve available languages.
</ParamField>

<ParamField body="type" type="string">
  The assistant type. Options: `inbound`, `outbound`
</ParamField>

<ParamField body="mode" type="string">
  The engine mode. Options: `pipeline`, `multimodal`, `dualplex`

  <Warning>
    Changing the mode resets mode-specific settings to their default values for the new mode.
  </Warning>
</ParamField>

<ParamField body="timezone" type="string">
  The timezone for the assistant (e.g., "Europe/Berlin", "America/New\_York")
</ParamField>

<ParamField body="initial_message" type="string">
  The initial message the assistant will speak at call start (max. 200 characters)
</ParamField>

<ParamField body="system_prompt" type="string">
  The system prompt defining the assistant's behaviour and personality
</ParamField>

#### Mode-Specific Fields

<ParamField body="llm_model_id" type="integer">
  The LLM model ID to use. Only applicable in `pipeline` mode.

  Use the [Get Models](/en/api-reference/assistants/models) endpoint to retrieve available models.
</ParamField>

<ParamField body="multimodal_model_id" type="integer">
  The multimodal model ID. Applicable only in `multimodal` and `dualplex` modes.

  Use the [Get Models](/en/api-reference/assistants/models) endpoint to retrieve available multimodal models.
</ParamField>

<ParamField body="chat_llm_fallback_id" type="integer">
  Fallback LLM model ID for tool calls in multimodal/dualplex modes. Set to `null` to remove.
</ParamField>

<ParamField body="turn_detection_threshold" type="number">
  Sensitivity of speaker turn detection for multimodal/dualplex modes (0-1). Set to `null` for automatic.
</ParamField>

#### Secondary Languages

<ParamField body="secondary_language_ids" type="integer[]">
  Array of additional language IDs the assistant can speak. Replaces existing secondary languages. Pass an empty array `[]` to remove all secondary languages.

  ```json theme={null} theme={null}
  "secondary_language_ids": [2, 3, 4]
  ```
</ParamField>

#### Knowledgebase Settings

<ParamField body="knowledgebase_id" type="integer">
  The ID of the knowledgebase to link. Set to `null` to remove.
</ParamField>

<ParamField body="knowledgebase_mode" type="string">
  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)
</ParamField>

#### Organization

<ParamField body="folder_id" type="integer">
  ID of a [folder](/en/api-reference/folders/create) to move this assistant into. Must belong to your account. Set to `null` to make it uncategorized. Omit to leave the folder unchanged.
</ParamField>

<ParamField body="label_ids" type="integer[]">
  Array of [label](/en/api-reference/labels/create) 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.

  ```json theme={null} theme={null}
  "label_ids": [3, 5]
  ```
</ParamField>

#### Phone Number

<ParamField body="phone_number_id" type="integer">
  The ID of a phone number to assign. Set to `null` to unassign. Must belong to your account.

  <Warning>
    For `inbound` assistants, the phone number cannot be a caller ID type and must not already be assigned to another inbound assistant.
  </Warning>
</ParamField>

#### Custom Mid-Call Tools

<ParamField body="tool_ids" type="integer[]">
  Array of custom mid-call tool IDs to synchronize. **Replaces all existing tool assignments.** Pass an empty array `[]` to remove all tools. Each tool must belong to your account.

  ```json theme={null} theme={null}
  "tool_ids": [1, 5, 12]
  ```
</ParamField>

#### Built-in Tools

<ParamField body="tools" type="array">
  Array of built-in tools. **Replaces all existing built-in tools.** Pass an empty array `[]` to remove all tools.

  <Expandable title="Tool Types">
    **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. See [Get Phone Numbers](/en/api-reference/assistants/phone-numbers).
    * `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

    * `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_booking_fields`: Array of custom booking fields for the event. Each field has: `slug` (required), `type` (required, e.g. “text”, “email”, “phone”, “select”), `label` (required), `required` (default: `false`), `options` (array of options for select fields)
    * `description`: When to offer scheduling

    **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`)
  </Expandable>

  ```json theme={null} theme={null}
  "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"
    }
  ]
  ```

  <Note>
    When you [list assistants](/en/api-reference/assistants/list), each configured tool is returned as `{ "type": "...", "data": { ... } }` with the same field names nested under `data` (not top-level).
  </Note>
</ParamField>

#### Speech and TTS Settings

<ParamField body="tts_emotion_enabled" type="boolean">
  Whether emotional text-to-speech synthesis is enabled
</ParamField>

<ParamField body="voice_stability" type="number">
  Voice stability setting (0-1). Higher = more consistent voice
</ParamField>

<ParamField body="voice_similarity" type="number">
  Voice similarity setting (0-1). Higher = closer to original voice
</ParamField>

<ParamField body="speech_speed" type="number">
  Speech speed multiplier (0.7-1.2)
</ParamField>

<ParamField body="llm_temperature" type="number">
  LLM temperature setting (0-1). Lower = more deterministic
</ParamField>

<ParamField body="synthesizer_provider_id" type="integer">
  Custom TTS provider ID. Set to `null` to use the system default voice. See [Get Synthesizer Providers](/en/api-reference/assistants/synthesizer-providers).
</ParamField>

<ParamField body="transcriber_provider_id" type="integer">
  Custom STT provider ID. Pipeline mode only. Set to `null` to use the system default voice. See [Get Transcriber Providers](/en/api-reference/assistants/transcriber-providers).
</ParamField>

#### Call Behavior Settings

<ParamField body="allow_interruptions" type="boolean">
  Whether caller interruptions are allowed.

  <Warning>Cannot be disabled in `multimodal` and `dualplex` modes.</Warning>
</ParamField>

<ParamField body="fillers" type="boolean">
  Whether filler audio should be used during processing.

  <Warning>Available only in `pipeline` mode.</Warning>
</ParamField>

<ParamField body="filler_config" type="object">
  Custom filler profiles per category. Replaces the existing filler configuration. Each category is an array of short phrases.

  * `positive`: Fillers for affirmative responses
  * `negative`: Fillers for negative/neutral responses
  * `question`: Fillers when processing a question
  * `neutral`: Fillers for neutral confirmations

  ```json theme={null} theme={null}
  "filler_config": {
    "positive": ["Great!", "Perfect!"],
    "negative": ["Hmm.", "Understood."],
    "question": ["Good question.", "One moment."],
    "neutral": ["Okay.", "Noted."]
  }
  ```
</ParamField>

<ParamField body="record" type="boolean">
  Whether the call should be recorded
</ParamField>

<ParamField body="enable_noise_cancellation" type="boolean">
  Whether noise cancellation should be enabled
</ParamField>

<ParamField body="wait_for_customer" type="boolean">
  If true, the assistant waits for the customer to speak first
</ParamField>

#### Timing Settings

<ParamField body="max_duration" type="integer">
  Maximum call duration in seconds (20-1200)
</ParamField>

<ParamField body="max_silence_duration" type="integer">
  Maximum silence duration before re-engagement in seconds (1-360)
</ParamField>

<ParamField body="max_initial_silence_duration" type="integer">
  Maximum silence at the start of the call before termination (1-120 seconds). Set to `null` to disable.
</ParamField>

<ParamField body="ringing_time" type="integer">
  Maximum ringing time before aborting (1-60 seconds)
</ParamField>

#### Re-Engagement Settings

<ParamField body="reengagement_interval" type="integer">
  Interval for re-engagement in seconds (7-600)
</ParamField>

<ParamField body="reengagement_prompt" type="string">
  Custom prompt for re-engagement messages (max. 1000 characters). Set to `null` to use the default.
</ParamField>

#### Voicemail Settings

<ParamField body="end_call_on_voicemail" type="boolean">
  Whether to end the call when voicemail is detected
</ParamField>

<ParamField body="voice_mail_message" type="string">
  Message to leave on voicemail before hanging up (max. 1000 characters). Set to `null` to disable.
</ParamField>

#### Endpoint Detection

<ParamField body="endpoint_type" type="string">
  Type of voice activity detection. Options: `vad`, `ai`
</ParamField>

<ParamField body="endpoint_sensitivity" type="number">
  Endpoint sensitivity level (0-5)
</ParamField>

<ParamField body="interrupt_sensitivity" type="number">
  Interruption sensitivity level (0-5)
</ParamField>

<ParamField body="min_interrupt_words" type="integer">
  Minimum number of words before interruption is allowed (0-10). Set to `null` to disable.
</ParamField>

#### Ambient Sound

<ParamField body="ambient_sound" type="string">
  Background ambient sound. Options: `off`, `office`, `city`, `forest`, `crowded_room`, `cafe`, `nature`
</ParamField>

<ParamField body="ambient_sound_volume" type="number">
  Volume of the ambient sound (0-1)
</ParamField>

#### Webhook Configuration

<ParamField body="is_webhook_active" type="boolean">
  Whether webhook notifications are enabled
</ParamField>

<ParamField body="webhook_url" type="string">
  The webhook URL for post-call notifications. Set to `null` to remove.
</ParamField>

<ParamField body="send_webhook_only_on_completed" type="boolean">
  Whether webhooks should be sent only for successfully completed calls (not on failed/no-answer)
</ParamField>

<ParamField body="include_recording_in_webhook" type="boolean">
  Whether the recording URL should be included in the webhook payload
</ParamField>

#### Post-Call Evaluation

<ParamField body="post_call_evaluation" type="boolean">
  Whether AI-based post-call evaluation is enabled
</ParamField>

<ParamField body="post_call_schema" type="array">
  Schema definition for extracting post-call data. Replaces the existing schema.

  <Expandable title="post_call_schema Properties">
    <ParamField body="name" type="string" required>
      Field name (3-16 characters, lowercase, alphanumeric and underscores only)
    </ParamField>

    <ParamField body="type" type="string" required>
      Data type. Options: `string`, `number`, `bool`
    </ParamField>

    <ParamField body="description" type="string" required>
      Description of what this field represents (3-255 characters)
    </ParamField>
  </Expandable>
</ParamField>

#### Variables

<ParamField body="variables" type="object">
  Key-value pairs for custom variables. **Replaces all existing variables.**

  ```json theme={null} theme={null}
  "variables": {
    "company_name": "Acme Corp",
    "product": "Premium Widget"
  }
  ```
</ParamField>

***

## Example Requests

### Update Basic Settings

```json theme={null} theme={null}
{
  "name": "Updated Assistant Name",
  "initial_message": "Hello! How can I help you today?",
  "max_duration": 900
}
```

### Switch to Multimodal Mode

```json theme={null} theme={null}
{
  "mode": "multimodal",
  "voice_id": 41,
  "multimodal_model_id": 1,
  "chat_llm_fallback_id": 2,
  "knowledgebase_mode": "function_call"
}
```

### Update Tools and Knowledgebase

```json theme={null} theme={null}
{
  "tool_ids": [1, 5, 12],
  "knowledgebase_id": 3,
  "knowledgebase_mode": "prompt"
}
```

### Update Re-Engagement and Voicemail

```json theme={null} theme={null}
{
  "reengagement_interval": 15,
  "reengagement_prompt": "Are you still there? I'm here to help.",
  "end_call_on_voicemail": true,
  "voice_mail_message": "Hello, please call us back at your earliest convenience."
}
```

### Remove Optional Settings

```json theme={null} theme={null}
{
  "phone_number_id": null,
  "webhook_url": null,
  "tool_ids": [],
  "secondary_language_ids": []
}
```

***

## Response

<ResponseField name="message" type="string">
  Success message confirming the assistant update
</ResponseField>

<ResponseField name="data" type="object">
  <Expandable title="Properties">
    <ResponseField name="id" type="integer">
      The unique ID of the updated assistant
    </ResponseField>

    <ResponseField name="name" type="string">
      The assistant’s name
    </ResponseField>

    <ResponseField name="status" type="string">
      The current status of the assistant
    </ResponseField>

    <ResponseField name="type" type="string">
      The type (`inbound` or `outbound`)
    </ResponseField>

    <ResponseField name="mode" type="string">
      The engine mode (`pipeline`, `multimodal`, or `dualplex`)
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseExample>
  ```json 200 Success theme={null} theme={null}
  {
    "message": "Assistant updated successfully",
    "data": {
      "id": 789,
      "name": "Updated Sales Assistant",
      "status": "active",
      "type": "outbound",
      "mode": "pipeline"
    }
  }
  ```

  ```json 404 Not Found theme={null} theme={null}
  {
    "message": "Assistant not found"
  }
  ```

  ```json 422 Validation Error theme={null} theme={null}
  {
    "message": "Validation failed",
    "errors": {
      "speech_speed": ["Speech speed must be between 0.7 and 1.2."],
      "voice_id": ["The selected voice is not compatible with the selected engine type."],
      "allow_interruptions": ["Interruptions cannot be disabled in multimodal or dualplex mode."]
    }
  }
  ```
</ResponseExample>

***

## Notes

* Only the fields you provide in the request body will be updated
* To remove optional fields, explicitly set them to `null`
* To clear arrays (tools, secondary languages), pass an empty array `[]`
* The assistant must belong to the authenticated user
* Use the [Get Voices](/en/api-reference/assistants/voices) endpoint with the `mode` parameter to get compatible voices
* For multimodal/dualplex modes, `knowledgebase_mode` must be set to `function_call`
* In multimodal/dualplex modes, interruptions (`allow_interruptions`) cannot be disabled
* Changing mode resets mode-specific settings (LLM model, multimodal model, providers)