# Parameter A type that monitors the state of its wrapped value to reevaluate any dependent tip rules when the value changes. ``` struct Parameter where Value : Decodable, Value : Encodable, Value : Sendable ``` ## Overview You create a parameter by wrapping a conforming type with the `@Parameter` macro. An `id` is generated based on the parameter’s enclosing instance and the name of the property it is wrapping. > Note: Parameters are persistent by default. Wrapping a property with `@Parameter` will persist its value between app launches within the tips datastore. > Passing ``doc://com.apple.TipKit/documentation/TipKit/Tips/ParameterOption/transient`` as an option will allow the parameter to reset to a default value the first time it is referenced. Tips must be configured using [`configure(_:)`](/documentation/TipKit/Tips/configure(_:)) before a parameter’s value will be updated. Pair parameters with the tip properties you want to monitor. For example, to track whether someone has previously used a feature in your app, define a property wrapper, along with the parameter with the value you want to track in your tip as follows: ```swift struct LandmarksUser { // Define the user interaction you want to use for a display rule. @Parameter static var hasFavoritedLandmark: Bool = false } ``` Then construct a rule for your tip based on that parameter: ```swift struct FavoriteLandmarkTip: Tip { var rules: [Rule] { // Tip will only display when `hasFavoritedLandmark` is false. #Rule(LandmarksUser.hasFavoritedLandmark) { $0 == false } } } ``` ## Topics ### Parameter options [`ParameterOption.transient`](/documentation/TipKit/Tips/ParameterOption/transient) An option that resets the parameter value the first time it is referenced. ## See Also [`Rule`](/documentation/TipKit/Tips/Rule) A condition to meet before displaying a tip. --- 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)