OpenAI (GPT)

Use OpenAI's GPT models as the LLM provider in a CompositeVoice pipeline.

Use OpenAILLM when you want GPT models for your voice assistant.

Prerequisites

An OpenAI API key or a CompositeVoice proxy server
Install the peer dependency:

npm install openai

Basic setup

import { CompositeVoice, OpenAILLM, NativeSTT, NativeTTS } from '@lukeocodes/composite-voice';

const agent = new CompositeVoice({
  stt: new NativeSTT({ language: 'en-US' }),
  llm: new OpenAILLM({
    proxyUrl: '/api/proxy/openai',
    model: 'gpt-4o-mini',
    systemPrompt: 'You are a concise voice assistant. Keep answers under two sentences.',
  }),
  tts: new NativeTTS(),
});

await agent.start();

Configuration options

Option	Type	Default	Description
`model`	`string`	(required)	Model identifier. See model variants below.
`systemPrompt`	`string`	—	System-level instructions for the assistant.
`temperature`	`number`	—	Randomness (0 = deterministic, 2 = creative).
`maxTokens`	`number`	—	Maximum tokens per response.
`topP`	`number`	—	Nucleus sampling threshold (0—1).
`stream`	`boolean`	`true`	Stream tokens incrementally.
`proxyUrl`	`string`	—	CompositeVoice proxy endpoint. Recommended for browsers.
`apiKey`	`string`	—	Direct API key. Use only in server-side code.
`organizationId`	`string`	—	OpenAI organization ID for multi-org accounts.
`maxRetries`	`number`	`3`	Retry count for failed requests.

Model variants

Model	Speed	Notes
`gpt-4o-mini`	Fast	Good balance of speed and quality for voice
`gpt-4o`	Moderate	High capability, multimodal
`gpt-4-turbo`	Moderate	Large context window
`gpt-3.5-turbo`	Fast	Lower cost, lower capability

Complete example

import {
  CompositeVoice,
  OpenAILLM,
  DeepgramSTT,
  DeepgramTTS,
} from '@lukeocodes/composite-voice';

const agent = new CompositeVoice({
  stt: new DeepgramSTT({
    proxyUrl: '/api/proxy/deepgram',
    language: 'en',
    options: { model: 'nova-3', smartFormat: true },
  }),
  llm: new OpenAILLM({
    proxyUrl: '/api/proxy/openai',
    model: 'gpt-4o-mini',
    temperature: 0.7,
    maxTokens: 256,
    systemPrompt: 'You are a friendly voice assistant. Answer briefly.',
  }),
  tts: new DeepgramTTS({
    proxyUrl: '/api/proxy/deepgram',
    voice: 'aura-2-thalia-en',
  }),
  conversationHistory: { enabled: true, maxTurns: 10 },
});

await agent.start();

Tips

model is required. OpenAILLM does not set a default model. You must specify one.
gpt-4o-mini is ideal for voice. It offers low latency and good quality for conversational use cases.
Use organizationId for multi-org accounts. If your API key belongs to multiple organizations, set this to route requests correctly.
OpenAILLM extends OpenAICompatibleLLM. All streaming, abort, and proxy logic is inherited from the base class.

Providers reference — all LLM providers at a glance
API reference — full class documentation
OpenAI Compatible guide — connect custom OpenAI-compatible endpoints

Prerequisites

Basic setup

Configuration options

Model variants

Complete example

Tips

Related