# ChatStreamingMessageChunk

Delta changes in streaming response


## Fields

| Field                                                                                                | Type                                                                                                 | Required                                                                                             | Description                                                                                          | Example                                                                                              |
| ---------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------- |
| `role`                                                                                               | [Optional[components.ChatStreamingMessageChunkRole]](../components/chatstreamingmessagechunkrole.md) | :heavy_minus_sign:                                                                                   | The role of the message author                                                                       | assistant                                                                                            |
| `content`                                                                                            | *OptionalNullable[str]*                                                                              | :heavy_minus_sign:                                                                                   | Message content delta                                                                                | Hello                                                                                                |
| `reasoning`                                                                                          | *OptionalNullable[str]*                                                                              | :heavy_minus_sign:                                                                                   | Reasoning content delta                                                                              | I need to                                                                                            |
| `refusal`                                                                                            | *OptionalNullable[str]*                                                                              | :heavy_minus_sign:                                                                                   | Refusal message delta                                                                                | <nil>                                                                                                |
| `tool_calls`                                                                                         | List[[components.ChatStreamingMessageToolCall](../components/chatstreamingmessagetoolcall.md)]       | :heavy_minus_sign:                                                                                   | Tool calls delta                                                                                     |                                                                                                      |
| `reasoning_details`                                                                                  | List[[components.ReasoningDetailUnion](../components/reasoningdetailunion.md)]                       | :heavy_minus_sign:                                                                                   | Reasoning details for extended thinking models                                                       |                                                                                                      |