> ## 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.

# ModelArchitecture

Model architecture information

## Fields

| Field | Type | Required | Description | Example |
| - | - | - | - | - |
| `input_modalities` | List\[[components.InputModality](../components/inputmodality.mdx)] | :heavy\_check\_mark: | Supported input modalities | |
| `instruct_type` | [OptionalNullable\[components.InstructType\]](../components/instructtype.mdx) | :heavy\_minus\_sign: | Instruction format type | chatml |
| `modality` | *Nullable\[str]* | :heavy\_check\_mark: | Primary modality of the model | text->text |
| `output_modalities` | List\[[components.OutputModality](../components/outputmodality.mdx)] | :heavy\_check\_mark: | Supported output modalities | |
| `tokenizer` | [Optional\[components.ModelGroup\]](../components/modelgroup.mdx) | :heavy\_minus\_sign: | Tokenizer type used by the model | GPT |