> ## Documentation Index
> Fetch the complete documentation index at: https://docs.screenjson.com/llms.txt
> Use this file to discover all available pages before exploring further.

# UUIDs and identity

> Every node that can be referenced from elsewhere carries an RFC 4122 UUID.

Every node in a ScreenJSON document that can be referenced from elsewhere carries an [RFC 4122](https://www.rfc-editor.org/rfc/rfc4122) UUID.

## Format

```
^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$
```

Example: `7a1c0b4e-8f3a-4c68-9d2e-ac8f21a0d8a4`.

## Nodes with UUIDs

| Node        | Where                                |
| ----------- | ------------------------------------ |
| Document    | root `id`                            |
| Author      | `authors[].id`                       |
| Contributor | `contributors[].id`                  |
| Character   | `characters[].id`                    |
| Scene       | `document.scenes[].id`               |
| Element     | `document.scenes[].body[].id`        |
| Note        | `notes[].id`                         |
| Revision    | `revisions[].id`                     |
| Bookmark    | `document.bookmarks[].id`            |
| Source      | `sources[].id`                       |
| Embedding   | `analysis.embeddings[<target>][].id` |
| Passage     | `analysis.passages[].id`             |
| Summary     | `analysis.summaries[].id`            |

## Cross-references

* `dialogue.character` and `character` (cue).character point to `characters[].id`.
* `note.contributor` points to `contributors[].id`.
* `note.parent` points to the element, scene, or note the annotation is attached to.
* `bookmark.scene` and `bookmark.element` point to their targets.
* `passage.scene` and `passage.elements[]` point to the elements a passage covers.
* `summary.target` points to a scene (when `scope = "scene"`).
* `element.scene` back-references its parent scene.
* `revision.parent` points to the revision it was forked from.

## Guarantees

* A given UUID identifies **one** node for the lifetime of the document.
* Regenerating output across a compatible change SHOULD reuse the same UUIDs, not mint new ones. Both `screenjson convert` and `screenjson-export` honour this when the output file already exists on disk.