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POST
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:

Request Body

Core Required Fields

string
required
The name of the assistant (max 255 characters)
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.
integer
required
The language ID for the assistant. Use the Get Languages endpoint to get available languages.
string
required
The assistant type. Options: inbound, outbound
string
required
The engine mode. Options: pipeline, multimodal, dualplex
string
required
The timezone for the assistant (e.g., “Europe/Bucharest”, “America/New_York”)
string
required
The initial message the assistant will speak when the call starts (max 200 characters)
string
required
The system prompt that defines the assistant’s behavior and personality

Mode-Specific Fields

integer
The LLM model ID to use. Required for pipeline mode.Use the Get Models endpoint to get available models.
integer
The multimodal model ID. Required for multimodal and dualplex modes.Use the Get Models endpoint to get available multimodal models.
integer
Fallback LLM model ID for tool calls in multimodal/dualplex modes. Optional.
number
Turn detection sensitivity for multimodal/dualplex modes (0-1). Default: auto

Secondary Languages

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

Knowledgebase Settings

integer
The knowledgebase ID to attach to this assistant
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

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

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

Built-in Tools

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

Voice and TTS Settings

boolean
default:"true"
Whether to enable emotional text-to-speech synthesis
number
default:"0.70"
Voice stability setting (0-1). Higher = more consistent voice
number
default:"0.50"
Voice similarity setting (0-1). Higher = closer to original voice
number
default:"1.00"
Speech speed multiplier (0.7-1.2)
number
default:"0.10"
LLM temperature setting (0-1). Lower = more deterministic
integer
Custom TTS provider ID. Auto-selected based on language if not provided.
integer
Custom STT provider ID. Auto-selected based on language if not provided. Pipeline mode only.

Call Behavior Settings

boolean
default:"true"
Whether to allow caller interruptions.
Cannot be disabled for multimodal and dualplex modes.
boolean
default:"false"
Whether to use filler audio during processing (e.g., “um”, “let me check”).
Only available for pipeline mode.
boolean
default:"false"
Whether to record the call
boolean
default:"true"
Whether to enable noise cancellation
boolean
default:"false"
If true, the assistant waits for the customer to speak first

Timing Settings

integer
default:"600"
Maximum call duration in seconds (20-1200)
integer
default:"40"
Maximum silence duration before re-engagement in seconds (1-360)
integer
Maximum silence at call start before ending (1-120 seconds). Optional.
integer
default:"30"
Maximum ringing time before giving up (1-60 seconds)

Re-engagement Settings

integer
default:"30"
Re-engagement interval in seconds (7-600)
string
Custom prompt for re-engagement messages (max 1000 characters)Example: "Are you still there? Do you have any other questions?"

Voicemail Settings

boolean
default:"true"
Whether to end call when voicemail is detected
string
Message to leave on voicemail before hanging up (max 1000 characters)

Endpoint Detection

string
default:"vad"
Voice activity detection type. Options: vad, ai
number
default:"0.5"
Endpoint sensitivity level (0-5)
number
default:"0.5"
Interrupt sensitivity level (0-5)
integer
Minimum words before interruption is allowed (0-10). Set to enable.

Ambient Sound

string
Background ambient sound. Options: off, office, city, forest, crowded_room, cafe, nature
number
default:"0.5"
Ambient sound volume level (0-1)

Webhook Configuration

boolean
default:"false"
Whether webhook notifications are enabled
string
The webhook URL for post-call notifications. Required if is_webhook_active is true.
boolean
default:"true"
Whether to send webhooks only on completed calls (not failed/no-answer)
boolean
default:"true"
Whether to include recording URL in webhook payload

Post-Call Evaluation

boolean
default:"true"
Whether to enable AI post-call evaluation
array
Schema definition for post-call data extraction

Variables

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

Example Requests

Pipeline Mode Assistant

Multimodal Mode Assistant

Dualplex Mode Assistant


Response

string
Success message confirming assistant creation
object

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