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

# Artifact and asset events

> Events emitted when artifacts and artifact collections are created or updated and when assets are referenced or materialized.

Artifact events track individual artifact creation and updates. Artifact
collection events track the lifecycle of keyed artifact collections. Asset
events track data lineage through upstream references and downstream
materializations.

## Artifact collection events

An artifact collection groups all artifacts that share the same key. Collection
lifecycle events are emitted when that collection is created, updated (the
latest artifact changes), or deleted (all artifacts for the key are removed).

### `prefect.artifact-collection.created`

Emitted when a keyed artifact collection is first created (that is, when the
first artifact with a given key is written).

#### Resource

| Label                   | Description                          |
| ----------------------- | ------------------------------------ |
| `prefect.resource.id`   | `prefect.artifact-collection.{uuid}` |
| `prefect.resource.name` | Artifact key                         |

#### Related resources

| Resource ID pattern       | Role       | When present                                                         |
| ------------------------- | ---------- | -------------------------------------------------------------------- |
| `prefect.artifact.{uuid}` | `latest`   | The artifact that is currently the latest version in this collection |
| `prefect.flow-run.{uuid}` | `flow-run` | When the artifact was created by a flow run                          |
| `prefect.task-run.{uuid}` | `task-run` | When the artifact was created by a task run                          |

#### Payload

| Field         | Type           | Description                                                           |
| ------------- | -------------- | --------------------------------------------------------------------- |
| `key`         | string         | Artifact key                                                          |
| `type`        | string or null | Artifact type (for example, `markdown`, `table`, `progress`, `image`) |
| `data`        | any or null    | Artifact data                                                         |
| `description` | string or null | Artifact description                                                  |

### `prefect.artifact-collection.updated`

Emitted when the latest artifact in a collection changes (for example, a new
artifact with the same key is written).

#### Resource

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated).

#### Related resources

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated), reflecting the new latest artifact.

#### Payload

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated).

### `prefect.artifact-collection.deleted`

Emitted when all artifacts for a key are removed and the collection is deleted.

#### Resource

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated).

#### Related resources

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated).

#### Payload

Same as [`prefect.artifact-collection.created`](#prefectartifact-collectioncreated).

## Artifact events

### `prefect.artifact.created`

Emitted when a new artifact is created.

#### Resource

| Label                   | Description               |
| ----------------------- | ------------------------- |
| `prefect.resource.id`   | `prefect.artifact.{uuid}` |
| `prefect.resource.name` | Artifact key (when set)   |

#### Related resources

This event has no related resources.

#### Payload

| Field         | Type           | Description                                                           |
| ------------- | -------------- | --------------------------------------------------------------------- |
| `key`         | string or null | Artifact key                                                          |
| `type`        | string or null | Artifact type (for example, `markdown`, `table`, `progress`, `image`) |
| `description` | string or null | Artifact description                                                  |

### `prefect.artifact.updated`

Emitted when an existing artifact is updated.

#### Resource

| Label                 | Description               |
| --------------------- | ------------------------- |
| `prefect.resource.id` | `prefect.artifact.{uuid}` |

#### Related resources

This event has no related resources.

#### Payload

The payload contains the fields that were updated, serialized from the update
model. Common fields include `data`, `description`, and `type`.

## Asset events

For more on assets and data lineage, see [Assets](/v3/concepts/assets).

### `prefect.asset.referenced`

Emitted for each upstream asset referenced during a task execution. One event is
emitted per upstream asset.

#### Resource

| Label                       | Description                                                                     |
| --------------------------- | ------------------------------------------------------------------------------- |
| `prefect.resource.id`       | Asset key (the unique identifier for the asset, for example `s3://bucket/path`) |
| `prefect.resource.name`     | Asset name (when set via asset properties)                                      |
| `prefect.asset.description` | Asset description (when set)                                                    |
| `prefect.asset.url`         | Asset URL (when set)                                                            |
| `prefect.asset.owners`      | JSON-encoded list of asset owners (when set)                                    |

#### Related resources

This event has no related resources.

#### Payload

This event has no payload.

### `prefect.asset.materialization.succeeded`

Emitted when a downstream asset is successfully materialized (the task that
produces it completes).

#### Resource

Same labels as [`prefect.asset.referenced`](#prefectassetreferenced).

#### Related resources

| Resource ID pattern        | Role                    | When present                                             |
| -------------------------- | ----------------------- | -------------------------------------------------------- |
| Asset key                  | `asset`                 | One entry per upstream asset (both direct and inherited) |
| Materialized-by identifier | `asset-materialized-by` | When a `materialized_by` identifier was specified        |

#### Payload

User-provided materialization metadata, if any was supplied via the asset's
`materialization_metadata` parameter. This is an open-ended dictionary.

### `prefect.asset.materialization.failed`

Emitted when a downstream asset fails to materialize (the task that produces it
fails). Same structure as
[`prefect.asset.materialization.succeeded`](#prefectassetmaterializationsucceeded).

#### Resource

Same labels as [`prefect.asset.referenced`](#prefectassetreferenced).

#### Related resources

Same as [`prefect.asset.materialization.succeeded`](#prefectassetmaterializationsucceeded).

#### Payload

Same as [`prefect.asset.materialization.succeeded`](#prefectassetmaterializationsucceeded).