Configuring LLM Settings

LLM settings select which managed language model generates the avatar’s responses in FULL Mode. The setting is a provider and model pair, configured either on a stored voice agent or inline on avatar_persona when creating a session token. If you omit llm_settings, the session uses the managed default model.

Supported models

LiveAvatar currently supports the following OpenAI models. Support for additional vendors and models is in progress.

Provider	Model	Notes
`openai`	`gpt-4o-mini`	Default
`openai`	`gpt-4o`
`openai`	`gpt-5-nano`
`openai`	`gpt-5.4-nano`

Retrieve the current catalog programmatically with List LLM Models. The response maps each provider to the models it accepts:

curl https://api.liveavatar.com/v1/llm-models \
  -H "X-API-KEY: <YOUR_API_KEY>"

{
  "code": 100,
  "data": {
    "openai": ["gpt-4o", "gpt-4o-mini", "gpt-5-nano", "gpt-5.4-nano"]
  },
  "message": "LLM models retrieved successfully"
}

A model not in this list is rejected with a 422 when you write it to a voice agent or a session token.

Schema

Field	Type	Default	Description
`provider`	string	`openai`	LLM vendor. Currently only `openai`.
`model`	string	`gpt-4o-mini`	Model identifier from the provider’s list in List LLM Models.

On a session token

Set llm_settings under avatar_persona when creating a session token. The choice applies to that session only.

{
  "mode": "FULL",
  "avatar_id": "<avatar_id>",
  "avatar_persona": {
    "voice_id": "<voice_id>",
    "context_id": "<context_id>",
    "language": "en",
    "llm_settings": {
      "provider": "openai",
      "model": "gpt-4o"
    }
  }
}

On a voice agent

A stored liveavatar_agent saves its own llm_settings as part of its agent_configuration. Every session that references the agent with voice_agent uses the stored model, so the choice is made once rather than on each session token. Retrieve an agent with Get Voice Agent to see which model it uses:

{
  "id": "<voice_agent_id>",
  "name": "Support agent",
  "agent_type": "liveavatar_agent",
  "agent_configuration": {
    "agent_type": "liveavatar_agent",
    "voice_id": "<voice_id>",
    "context_id": "<context_id>",
    "language": "en",
    "llm_settings": {
      "provider": "openai",
      "model": "gpt-4o"
    }
  }
}

An agent created without an explicit model is stored with the default, so llm_settings is always present on a liveavatar_agent. It does not apply to elevenlabs_agent or cartesia_agent, which run their own LLM on the provider side.

Interaction with custom LLMs

llm_settings selects a managed model that LiveAvatar hosts. A custom LLM configured with llm_configuration_id replaces the managed model with your own endpoint and key. Today these are two separate settings and cannot be combined.

llm_configuration_id and llm_settings are mutually exclusive.
A session token that sets both avatar_persona.llm_settings and llm_configuration_id is rejected with a 400.
Referencing a stored liveavatar_agent with voice_agent alongside llm_configuration_id is also rejected, since stored agents always carry llm_settings.
To use a custom LLM, configure the session with avatar_persona and omit llm_settings.

We are working on unifying custom LLM configuration with llm_settings so that a single setting covers both managed and bring-your-own models. Expect this section to change.

Custom LLM endpoints are not listed by List LLM Models.

Getting Started

Core Concepts

FULL Mode

Avatar Only (LITE mode)

Socials

FAQ

Supported models

Schema

On a session token

On a voice agent

Interaction with custom LLMs

​Supported models

​Schema

​On a session token

​On a voice agent

​Interaction with custom LLMs

Supported models

Schema

On a session token

On a voice agent

Interaction with custom LLMs