> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # ToolChoiceSupport Per-variant `tool_choice` support. `tool_choice` in `supported_parameters` only says the parameter is accepted; these flags say which of its values passed testing. ## Fields | Field | Type | Required | Description | | ---------- | ------ | -------------------- | -------------------------------------------------------------------------------------------- | | `Auto` | `bool` | :heavy\_check\_mark: | Whether the endpoint supports `"tool_choice": "auto"`. | | `Function` | `bool` | :heavy\_check\_mark: | Whether the endpoint supports naming a function, `"tool_choice": {"type": "function", ...}`. | | `None` | `bool` | :heavy\_check\_mark: | Whether the endpoint supports `"tool_choice": "none"`. | | `Required` | `bool` | :heavy\_check\_mark: | Whether the endpoint supports `"tool_choice": "required"`. |