> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter-d02e98a0-mintlify-a46887cf.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# AnnotationAddedEvent - Go SDK

> AnnotationAddedEvent type definition

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

Event emitted when a text annotation is added to output

## Fields

| Field             | Type                                                                                                   | Required             | Description | Example                                                                                          |
| ----------------- | ------------------------------------------------------------------------------------------------------ | -------------------- | ----------- | ------------------------------------------------------------------------------------------------ |
| `Annotation`      | [components.OpenAIResponsesAnnotation](/client-sdks/go/api-reference/models/openairesponsesannotation) | :heavy\_check\_mark: | N/A         | `{"file_id": "file-abc123","filename": "research_paper.pdf","index": 0,"type": "file_citation"}` |
| `AnnotationIndex` | `int64`                                                                                                | :heavy\_check\_mark: | N/A         |                                                                                                  |
| `ContentIndex`    | `int64`                                                                                                | :heavy\_check\_mark: | N/A         |                                                                                                  |
| `ItemID`          | `string`                                                                                               | :heavy\_check\_mark: | N/A         |                                                                                                  |
| `OutputIndex`     | `int64`                                                                                                | :heavy\_check\_mark: | N/A         |                                                                                                  |
| `SequenceNumber`  | `int64`                                                                                                | :heavy\_check\_mark: | N/A         |                                                                                                  |
| `Type`            | [components.AnnotationAddedEventType](/client-sdks/go/api-reference/models/annotationaddedeventtype)   | :heavy\_check\_mark: | N/A         |                                                                                                  |