---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/llm/openai_responses/types/interfaces/OpenAIResponsesOutputTextDeltaEvent.md
description: >-
  SSE event emitted when a text fragment streams in for an output message's
  content.
---

# Interface: OpenAIResponsesOutputTextDeltaEvent

Defined in: [src/batteries/llm/openai\_responses/types.ts:334](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L334)

SSE event emitted when a text fragment streams in for an output message's content.

## Extends

* `OpenAIResponsesStreamEventBase`

## Properties

| Property                                                 | Type                           | Description                                                                | Overrides                             | Inherited from                                   | Defined in                                                                                                                                              |
| -------------------------------------------------------- | ------------------------------ | -------------------------------------------------------------------------- | ------------------------------------- | ------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
|  `content_index`      | `number`                       | The index of the content part within the item's `content` array.           | -                                     | -                                                | [src/batteries/llm/openai\_responses/types.ts:342](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L342) |
|  `delta`                      | `string`                       | The incremental text fragment to append.                                   | -                                     | -                                                | [src/batteries/llm/openai\_responses/types.ts:344](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L344) |
|  `item_id`                  | `string`                       | The id of the output-message item this delta belongs to.                   | -                                     | -                                                | [src/batteries/llm/openai\_responses/types.ts:338](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L338) |
|  `output_index`        | `number`                       | The index of the output-message item within `response.output`.             | -                                     | -                                                | [src/batteries/llm/openai\_responses/types.ts:340](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L340) |
|  `sequence_number?` | `number`                       | Monotonically increasing sequence number for this event within the stream. | -                                     | `OpenAIResponsesStreamEventBase.sequence_number` | [src/batteries/llm/openai\_responses/types.ts:310](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L310) |
|  `type`                        | `"response.output_text.delta"` | Event-type discriminator; always `'response.output_text.delta'`.           | `OpenAIResponsesStreamEventBase.type` | -                                                | [src/batteries/llm/openai\_responses/types.ts:336](https://github.com/NHTIO/ADK/blob/v1.20261003.0/src/src/batteries/llm/openai_responses/types.ts#L336) |