When you adopt SiriKit and support system or custom intents, you can give people powerful, convenient ways to interact with your app. For example, people can use hands-free interactions or suggestions on the Siri watch face to perform your app's tasks without ever opening your app.
The Shortcuts app is available in watchOS 7 and later, letting people view and invoke shortcuts that they create on their paired iPhone. A shortcut can also run on Apple Watch when there's a watchOS app that supports it, although the app may hand off some steps to the paired iPhone for completion. The more intents you support in your watchOS app, the more shortcuts your app can run directly on Apple Watch.
Consider creating shortcuts for your app's actions that can appear on the Siri watch face. Shortcuts make it easy for people to perform essential actions that your app supports. To ensure that your shortcut is eligible to appear on the Siri watch face, you need to define the relevance of the shortcut. You define relevance by giving the system details about a shortcut's action, such as the date, time of day, or location when it's likely to be useful to people. The system uses these details (also known as parameters) to determine the context in which to offer the shortcut on the Siri watch face. For developer guidance, see Defining Relevant Shortcuts for Your App.
TIP You don't need a watchOS app to supply relevant shortcuts for the Siri watch face, but you do need a watchOS app to run shortcuts on Apple Watch.
Keep Siri interactions simple. People expect every interaction on Apple Watch to be quick and direct. You can help meet these expectations by supporting background operation and by designing clear and concise Siri interactions.
Make sure people can complete an action without leaving their current context. On Apple Watch, the best intents enable actions that run quickly and don't require people to retrieve their iPhone. When you support background operation, you help people complete a task in hands-free and voice-only scenarios on Apple Watch, in addition to other devices like HomePod and AirPods Pro. For developer guidance, see Running watchOS Apps in the Background.