# CommandLineArgsCallbackAnnotation Properties

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

Represents an annotation that provides a callback to be executed with a list of command-line arguments when an executable resource is started.

## Callback

- Name: `Callback`
- Modifiers: `get`
- Returns: `Func<CommandLineArgsCallbackContext, Task>`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/ApplicationModel/CommandLineArgsCallbackAnnotation.cs#L49)

Gets the callback action to be executed when the executable arguments are parsed.

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