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# CustomAppIntentErrorConvertible

A type that the system automatically converts to an app intent error.

```
protocol CustomAppIntentErrorConvertible
```

## Overview

Conform your custom type to this protocol when you need full control over the
[`AppIntentError`](/documentation/AppIntents/AppIntentError) that the system produces — including the error kind and localized description.
When you throw a conforming error from a method such as [`perform()`](/documentation/AppIntents/AppIntent/perform()) or
[`entities(for:)`](/documentation/AppIntents/EntityQuery/entities(for:)), the framework reads the [`appIntentError`](/documentation/AppIntents/CustomAppIntentErrorConvertible/appIntentError) property
and uses it directly.

If an error conforms to both
<doc://com.apple.documentation/documentation/Foundation/CustomLocalizedStringResourceConvertible> and
[`CustomAppIntentErrorConvertible`](/documentation/AppIntents/CustomAppIntentErrorConvertible), the system uses only [`CustomAppIntentErrorConvertible`](/documentation/AppIntents/CustomAppIntentErrorConvertible).

## Topics

### Instance Properties

[`var appIntentError: AppIntentError`](/documentation/AppIntents/CustomAppIntentErrorConvertible/appIntentError)

---

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