# PipelineConfigurationAnnotation Properties

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [PipelineConfigurationAnnotation](/reference/api/csharp/aspire.hosting/pipelineconfigurationannotation.md)
- Kind: `Properties`
- Members: `1`

An annotation that registers a callback to execute during the pipeline configuration phase, allowing modification of step dependencies and relationships.

## Callback

- Name: `Callback`
- Modifiers: `get`
- Returns: `Func<PipelineConfigurationContext, Task>`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/Pipelines/PipelineConfigurationAnnotation.cs#L21)

Gets the callback function to execute during the configuration phase.

```csharp
public Func<PipelineConfigurationContext, Task> Callback { get; }
```