The tool calls generated by the model, such as function calls.

Output types that you would like the model to generate for this request.
Most models are capable of generating text, which is the default:

["text"]

The gpt-4o-audio-preview model can also be used to generate audio. To
request that this model generate both text and audio responses, you can
use:

["text", "audio"]

Specifies a tool the model should use. Use to force the model to call a specific function.