> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-7021d5f4.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ChatStreamToolCall - Go SDK

> ChatStreamToolCall type definition

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

Tool call delta for streaming responses

## Fields

| Field      | Type                                                                                                       | Required             | Description                  | Example      |
| ---------- | ---------------------------------------------------------------------------------------------------------- | -------------------- | ---------------------------- | ------------ |
| `Function` | [\*components.ChatStreamToolCallFunction](/client-sdks/go/api-reference/models/chatstreamtoolcallfunction) | :heavy\_minus\_sign: | Function call details        |              |
| `ID`       | `*string`                                                                                                  | :heavy\_minus\_sign: | Tool call identifier         | call\_abc123 |
| `Index`    | `int64`                                                                                                    | :heavy\_check\_mark: | Tool call index in the array | 0            |
| `Type`     | [\*components.ChatStreamToolCallType](/client-sdks/go/api-reference/models/chatstreamtoolcalltype)         | :heavy\_minus\_sign: | Tool call type               | function     |