# delegate A delegate to which the session provides state change updates. ``` weak var delegate: (any AEAssessmentSessionDelegate)? { get set } ``` ## Discussion An assessment session operates asynchronously because it takes time to make the changes associated with starting or stopping a session, and external events might affect the state of the session. Adopt the [`AEAssessmentSessionDelegate`](/documentation/AutomaticAssessmentConfiguration/AEAssessmentSessionDelegate) protocol to receive callbacks at key points in the session life cycle. Store your adopter in the session’s [`delegate`](/documentation/AutomaticAssessmentConfiguration/AEAssessmentSession/delegate) property before starting a session. By listening for delegate callbacks, you learn when you can safely start an assessment after calling the session’s [`begin()`](/documentation/AutomaticAssessmentConfiguration/AEAssessmentSession/begin()) method, when the session has finished after calling the [`end()`](/documentation/AutomaticAssessmentConfiguration/AEAssessmentSession/end()) method, or if the session has been interrupted for some reason. The session calls all delegate methods on the main thread. --- Copyright © 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)