Force the model to use tools in a specific way.
| Mode | Description |
|---|---|
| "auto" | The default model behavior. The model decides whether to predict a function call or a natural language response. |
| "any" | The model must predict only function calls. To limit the model to a subset of functions, define the allowed function names in allowed_function_names. |
| "none" | The model must not predict function calls. This behavior is equivalent to a model request without any associated function declarations. |
| string | The string value must be one of the function names. This will force the model to predict the specified function call. |
The tool configuration's "any" mode ("forced function calling") is supported for Gemini 1.5 Pro models only.
tool_choice: string | Record<string, any>