You can use the `createUnsafeChatAdapter` function to create a OpenAI adapter as shown below:

```jsx
const openAiAdapter = createUnsafeChatAdapter()
    .withApiKey('your-openai-api-key-here')
    .withModel('gpt-3.5-turbo')
    .withSystemMessage('Act as a helpful assistant and be funny and engaging.');
```

The `createUnsafeChatAdapter` function returns an adapter builder that you can be configured by chaining methods.
Please refer to the [reference documentation](/reference/adapters/open-ai) for more information on the available methods.