Create assistant

This endpoint allows you to create a new AI assistant with comprehensive configuration options.

Engine Modes

The API supports three engine modes, each with different capabilities:

Mode	Description	Required Fields
`pipeline`	Traditional STT → LLM → TTS pipeline	`llm_model_id`
`multimodal`	Real-time multimodal AI	`multimodal_model_id`
`dualplex`	Multimodal brain + custom TTS voice	`multimodal_model_id`

Request Body

Core Required Fields

name

string

required

The name of the assistant (max 255 characters)

voice_id

integer

required

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_id

integer

required

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

type

string

required

The assistant type. Options: inbound, outbound

mode

string

required

The engine mode. Options: pipeline, multimodal, dualplex

timezone

string

required

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

initial_message

string

required

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

system_prompt

string

required

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

Mode-Specific Fields

llm_model_id

integer

The LLM model ID to use. Required for pipeline mode.Use the Get Models endpoint to get available models.

multimodal_model_id

integer

The multimodal model ID. Required for multimodal and dualplex modes.Use the Get Models endpoint to get available multimodal models.

chat_llm_fallback_id

integer

Fallback LLM model ID for tool calls in multimodal/dualplex modes. Optional.

turn_detection_threshold

number

Turn detection sensitivity for multimodal/dualplex modes (0-1). Default: auto

Secondary Languages

secondary_language_ids

integer[]

Array of additional language IDs the assistant can speak. The assistant will auto-detect and switch languages.

"secondary_language_ids": [2, 3, 4]

Knowledgebase Settings

knowledgebase_id

integer

The knowledgebase ID to attach to this assistant

knowledgebase_mode

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)

Phone Number

phone_number_id

integer

The ID of a phone number to assign to the assistant. 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.

Custom Mid-Call Tools

tool_ids

integer[]

Array of custom mid-call tool IDs to attach. Each tool must belong to your account.

"tool_ids": [1, 5, 12]

Built-in Tools

tools

array

Array of built-in tools to enable. Each tool has a type and tool-specific fields.

Show Tool types

call_transfer - Transfer the call to another phone number

phone_number (required): Phone number to transfer to (e.g., “+1234567890”)
description: When to transfer the call
custom: If true, AI can determine transfer number dynamically
timezone: Timezone for transfer availability

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)

calendar_integration - Schedule appointments via Cal.com

calcom_api_key (required): Your Cal.com API key
calcom_event_slug (required): The event type slug
description: When to offer scheduling

"tools": [
  {
    "type": "call_transfer",
    "phone_number": "+1234567890",
    "description": "Transfer when customer requests human support"
  },
  {
    "type": "dtmf_input",
    "description": "Navigate IVR menus when needed"
  },
  {
    "type": "end_call",
    "description": "End call when customer confirms satisfaction"
  }
]

Voice and TTS Settings

tts_emotion_enabled

boolean

default:"true"

Whether to enable emotional text-to-speech synthesis

voice_stability

number

default:"0.70"

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

voice_similarity

number

default:"0.50"

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

speech_speed

number

default:"1.00"

Speech speed multiplier (0.7-1.2)

llm_temperature

number

default:"0.10"

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

synthesizer_provider_id

integer

Custom TTS provider ID. Auto-selected based on language if not provided.

transcriber_provider_id

integer

Custom STT provider ID. Auto-selected based on language if not provided. Pipeline mode only.

Call Behavior Settings

allow_interruptions

boolean

default:"true"

Whether to allow caller interruptions.

Cannot be disabled for multimodal and dualplex modes.

fillers

boolean

default:"false"

Whether to use filler audio during processing (e.g., “um”, “let me check”).

Only available for pipeline mode.

record

boolean

default:"false"

Whether to record the call

enable_noise_cancellation

boolean

default:"true"

Whether to enable noise cancellation

wait_for_customer

boolean

default:"false"

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

Timing Settings

max_duration

integer

default:"600"

Maximum call duration in seconds (20-1200)

max_silence_duration

integer

default:"40"

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

max_initial_silence_duration

integer

Maximum silence at call start before ending (1-120 seconds). Optional.

ringing_time

integer

default:"30"

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

Re-engagement Settings

reengagement_interval

integer

default:"30"

Re-engagement interval in seconds (7-600)

reengagement_prompt

string

Custom prompt for re-engagement messages (max 1000 characters)Example: "Are you still there? Do you have any other questions?"

Voicemail Settings

end_call_on_voicemail

boolean

default:"true"

Whether to end call when voicemail is detected

voice_mail_message

string

Message to leave on voicemail before hanging up (max 1000 characters)

Endpoint Detection

endpoint_type

string

default:"vad"

Voice activity detection type. Options: vad, ai

endpoint_sensitivity

number

default:"0.5"

Endpoint sensitivity level (0-5)

interrupt_sensitivity

number

default:"0.5"

Interrupt sensitivity level (0-5)

min_interrupt_words

integer

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

Ambient Sound

ambient_sound

string

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

ambient_sound_volume

number

default:"0.5"

Ambient sound volume level (0-1)

Webhook Configuration

is_webhook_active

boolean

default:"false"

Whether webhook notifications are enabled

webhook_url

string

The webhook URL for post-call notifications. Required if is_webhook_active is true.

send_webhook_only_on_completed

boolean

default:"true"

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

include_recording_in_webhook

boolean

default:"true"

Whether to include recording URL in webhook payload

Post-Call Evaluation

post_call_evaluation

boolean

default:"true"

Whether to enable AI post-call evaluation

post_call_schema

array

Schema definition for post-call data extraction

Show post_call_schema properties

name

string

required

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

type

string

required

Data type. Options: string, number, bool

description

string

required

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

"post_call_schema": [
  {"name": "status", "type": "bool", "description": "Was the call objective achieved"},
  {"name": "summary", "type": "string", "description": "Brief summary of the call"}
]

Variables

variables

object

Key-value pairs of custom variables accessible in prompts via {{variable_name}}

"variables": {
  "company_name": "Acme Corp",
  "product": "Premium Widget",
  "support_email": "[email protected]"
}

Example Requests

Pipeline Mode Assistant

{
  "name": "Sales Assistant",
  "voice_id": 1,
  "language_id": 1,
  "type": "outbound",
  "mode": "pipeline",
  "timezone": "Europe/Bucharest",
  "initial_message": "Hello! How can I help you today?",
  "system_prompt": "You are a professional sales assistant...",
  "llm_model_id": 2,
  "secondary_language_ids": [2, 3],
  "knowledgebase_id": 1,
  "knowledgebase_mode": "prompt",
  "fillers": true,
  "tool_ids": [1, 5],
  "tools": [
    {"type": "end_call", "description": "End call when customer is satisfied"},
    {"type": "call_transfer", "phone_number": "+1234567890", "description": "Transfer to support"}
  ],
  "reengagement_interval": 20,
  "reengagement_prompt": "Are you still there?"
}

Multimodal Mode Assistant

{
  "name": "Support Bot",
  "voice_id": 41,
  "language_id": 1,
  "type": "inbound",
  "mode": "multimodal",
  "timezone": "America/New_York",
  "initial_message": "Hi! Welcome to support.",
  "system_prompt": "You are a helpful support agent...",
  "multimodal_model_id": 1,
  "chat_llm_fallback_id": 2,
  "turn_detection_threshold": 0.7,
  "knowledgebase_id": 1,
  "knowledgebase_mode": "function_call",
  "tts_emotion_enabled": false
}

Dualplex Mode Assistant

{
  "name": "Premium Agent",
  "voice_id": 1,
  "language_id": 2,
  "type": "outbound",
  "mode": "dualplex",
  "timezone": "Europe/Bucharest",
  "initial_message": "Buna ziua!",
  "system_prompt": "Esti un asistent profesionist...",
  "multimodal_model_id": 4,
  "chat_llm_fallback_id": 2,
  "secondary_language_ids": [1, 3],
  "knowledgebase_id": 1,
  "knowledgebase_mode": "function_call",
  "ambient_sound": "office",
  "ambient_sound_volume": 0.3
}

Response

message

string

Success message confirming assistant creation

data

object

Show properties

integer

The unique identifier of the created assistant

name

string

The name of the assistant

status

string

The current status (inactive for new assistants)

type

string

The type (inbound or outbound)

mode

string

The engine mode (pipeline, multimodal, or dualplex)

{
  "message": "Assistant created successfully",
  "data": {
    "id": 789,
    "name": "Sales Assistant",
    "status": "inactive",
    "type": "outbound",
    "mode": "pipeline"
  }
}

Notes

All required fields must be provided for successful assistant creation
Use the Get Voices endpoint with mode parameter to get compatible voices
For multimodal/dualplex modes, knowledgebase_mode must be function_call
For multimodal/dualplex modes, allow_interruptions is always enabled
Fillers are only available in pipeline mode
The assistant is created with inactive status by default

API Reference

Assistants

Calls

Conversations

AI

Mid Call Tools

Leads

Campaigns

Phone Numbers

Knowledgebases

SMS

Webhooks

API Keys

Create assistant

Engine Modes

Request Body

Core Required Fields

Mode-Specific Fields

Secondary Languages

Knowledgebase Settings

Phone Number

Custom Mid-Call Tools

Built-in Tools

Voice and TTS Settings

Call Behavior Settings

Timing Settings

Re-engagement Settings

Voicemail Settings

Endpoint Detection

Ambient Sound

Webhook Configuration

Post-Call Evaluation

Variables

Example Requests

Pipeline Mode Assistant

Multimodal Mode Assistant

Dualplex Mode Assistant

Response

Notes

API Reference

Assistants

Calls

Conversations

AI

Mid Call Tools

Leads

Campaigns

Phone Numbers

Knowledgebases

SMS

Webhooks

API Keys

​Engine Modes

​Request Body

​Core Required Fields

​Mode-Specific Fields

​Secondary Languages

​Knowledgebase Settings

​Phone Number

​Custom Mid-Call Tools

​Built-in Tools

​Voice and TTS Settings

​Call Behavior Settings

​Timing Settings

​Re-engagement Settings

​Voicemail Settings

​Endpoint Detection

​Ambient Sound

​Webhook Configuration

​Post-Call Evaluation

​Variables

​Example Requests

​Pipeline Mode Assistant

​Multimodal Mode Assistant

​Dualplex Mode Assistant

​Response

​Notes

Engine Modes

Request Body

Core Required Fields

Mode-Specific Fields

Secondary Languages

Knowledgebase Settings

Phone Number

Custom Mid-Call Tools

Built-in Tools

Voice and TTS Settings

Call Behavior Settings

Timing Settings

Re-engagement Settings

Voicemail Settings

Endpoint Detection

Ambient Sound

Webhook Configuration

Post-Call Evaluation

Variables

Example Requests

Pipeline Mode Assistant

Multimodal Mode Assistant

Dualplex Mode Assistant

Response

Notes