> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-5b6e02fd.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ChatStreamToolCall - Python SDK

> ChatStreamToolCall method reference

<Warning>
  The Python SDK and docs are currently in beta.
  Report issues on [GitHub](https://github.com/OpenRouterTeam/python-sdk/issues).
</Warning>

Tool call delta for streaming responses

## Fields

| Field      | Type                                                                                             | Required             | Description                  | Example      |
| ---------- | ------------------------------------------------------------------------------------------------ | -------------------- | ---------------------------- | ------------ |
| `function` | [Optional\[components.ChatStreamToolCallFunction\]](../components/chatstreamtoolcallfunction.md) | :heavy\_minus\_sign: | Function call details        |              |
| `id`       | *Optional\[str]*                                                                                 | :heavy\_minus\_sign: | Tool call identifier         | call\_abc123 |
| `index`    | *int*                                                                                            | :heavy\_check\_mark: | Tool call index in the array | 0            |
| `type`     | [Optional\[components.ChatStreamToolCallType\]](../components/chatstreamtoolcalltype.md)         | :heavy\_minus\_sign: | Tool call type               | function     |