toolChoice
Controls which (if any) function is called by the model.
ToolChoice.None means the model will not call a function and instead generates a message.
ToolChoice.Auto means the model can pick between generating a message or calling a function.
Specifying a particular function via ToolChoice.Named (or ToolChoice.function) forces the model to call that function.
ToolChoice.None is the default when no functions are present.ToolChoice.Auto is the default if functions are present.