# updateActivity(uuid:adding:completion:) Adds metadata to a workout activity that you’ve already added to the workout builder. ``` func updateActivity(uuid UUID: UUID, adding metadata: [String : Any], completion: @escaping @Sendable (Bool, (any Error)?) -> Void) ``` ``` func updateActivity(uuid UUID: UUID, adding metadata: [String : Any]) async throws ``` ## Parameters `UUID` The workout activity’s universally unique identifier (UUID). `metadata` A dictionary containing the metadata keys and values to add to the workout activity. `completion` A callback handler that the system calls after updating the workout activity. The system calls the callback handler on an anonymous background queue. The callback handler takes the following parameters: - success: Contains if the builder successfully updates the activity. - error: If the `success` parameter is , this parameter contains information about the error; otherwise, it’s `nil`. ## Discussion You can call this method multiple times to incrementally add metadata to the workout activity. The system merges the new metadata with any existing metadata using . Calling this method after calling [`finishWorkout(completion:)`](/documentation/HealthKit/HKWorkoutBuilder/finishWorkout(completion:)) fails with an error. --- 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)