<!--
{
  "availability" : [
    "iOS: 27.0.0 -",
    "iPadOS: 27.0.0 -",
    "macCatalyst: 27.0.0 -",
    "macOS: 27.0.0 -",
    "tvOS: 27.0.0 -",
    "visionOS: 27.0.0 -",
    "watchOS: 27.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AppIntentsTesting",
  "identifier" : "/documentation/AppIntentsTesting/AppIntentTypeDefinition",
  "metadataVersion" : "0.1.0",
  "role" : "Protocol",
  "symbol" : {
    "kind" : "Protocol",
    "modules" : [
      "App Intents Testing"
    ],
    "preciseIdentifier" : "s:17AppIntentsTesting0A20IntentTypeDefinitionP"
  },
  "title" : "AppIntentTypeDefinition"
}
-->

# AppIntentTypeDefinition

A protocol that associates a definition type with its corresponding instance type.

```
protocol AppIntentTypeDefinition
```

## Overview

The `AppIntentTypeDefinition` bridges a definition type you use to retrieve your intent, entity, and enum type, and the type-erased
instance of your concrete intent, entity, or enum. For example, `AppIntentTypeDefinition` bridges [`AppEntityDefinition`](/documentation/AppIntentsTesting/AppEntityDefinition)
to the [`AnyAppEntity`](/documentation/AppIntentsTesting/AnyAppEntity). Validate that a given instance was produced from the correct definition using the [`isInstance(_:)`](/documentation/AppIntentsTesting/AppIntentTypeDefinition/isInstance(_:)) function.

## Topics

### Associated Types

[`associatedtype Instance : IntentValueConvertible`](/documentation/AppIntentsTesting/AppIntentTypeDefinition/Instance)

The instance type that corresponds to this definition type.

### Instance Methods

[`func isInstance(Self.Instance) throws`](/documentation/AppIntentsTesting/AppIntentTypeDefinition/isInstance(_:))

Validates that the provided value matches this definition’s type.

## Relationships

### Conforming Types

[`AppEnumDefinition`](/documentation/AppIntentsTesting/AppEnumDefinition)

[`AppEntityDefinition`](/documentation/AppIntentsTesting/AppEntityDefinition)

[`TransientAppEntityDefinition`](/documentation/AppIntentsTesting/TransientAppEntityDefinition)

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)