You can do this by associating an object with a stable identifier with the data inside the Live Activity or Widget.

For example, for a recipe app, you could instantiate a Live Activites attributes with the recipes id.

Then when you invoke your AppIntent, you can pass it as an argument, like so:

struct ExampleIntent: AppIntent {

    // Configure your intents title and description

    @Parameter(title: "id")
    var id: String?

    init() {} // A default initialiser is required to conform to Appintent

    init(id: String) {
        self.id = id
    }

    func perform() async throws -> IntentResult {
        // use self.id here
    }

}