---
title: "ApplyPatchCallOperationDiffDeltaEvent"
---

Incremental chunk of `operation.diff` for an `apply_patch_call`. Matches OpenAI's streaming shape.


## Fields

| Field                                                                                                              | Type                                                                                                               | Required                                                                                                           | Description                                                                                                        |
| ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------ |
| `delta`                                                                                                            | *str*                                                                                                              | :heavy_check_mark:                                                                                                 | N/A                                                                                                                |
| `item_id`                                                                                                          | *str*                                                                                                              | :heavy_check_mark:                                                                                                 | N/A                                                                                                                |
| `output_index`                                                                                                     | *int*                                                                                                              | :heavy_check_mark:                                                                                                 | N/A                                                                                                                |
| `sequence_number`                                                                                                  | *int*                                                                                                              | :heavy_check_mark:                                                                                                 | N/A                                                                                                                |
| `type`                                                                                                             | [components.ApplyPatchCallOperationDiffDeltaEventType](../components/applypatchcalloperationdiffdeltaeventtype.mdx) | :heavy_check_mark:                                                                                                 | N/A                                                                                                                |