Watchface with Alarm (Vibrate)

As you found, Attention isn't available in watch faces, so your only option is something visual. Here's a case where HermoT had a message that he wanted to display of a condition detected by the watchface where he uses a popup on the watch face to indicate it:
https://forums.garmin.com/forum/developers/connect-iq/connect-iq-showcase/1229771-tidalface?p=1243070#post1243070

Hi Jim,
Don't you have a "nice" channel to the Garmin developper team? They could allow Attention to be used by a WatchFace!
Thanks
Marcel

Adding Attention access for watch faces has been requested a number of times here in the forum over the years, and the answer is always "no".

I cant understand the product manager of Garmin. And there is also no menu you could add such an alarm to the watch. This could be helpful for people with heart deseases. But obviously these are not customers of Garmin is interested in!

I requested it too before (in case you are interested in reading: https://forums.garmin.com/forum/deve...ect-iq/157858- ) and I concur that there are many use cases where it would be useful and I don't think it would require a lot of power as the vibrations would be something that is very rare in occurence (and watch faces that vibrate often would be self regulating as their users would de-install them)

I did the request when I didn't have plans to write a watch face yet. Since I now did anyway I'm even more fan of the idea of adding the vibrate functionality to watch faces (as it would require very little effort for me to add the functionality that I want to add). The product team has made it pretty clear that the attention module is not in scope of what watch faces are designed to do, so there's very slim chances that a watch face will be able to do vibrations ever.

The API that is designed to draw the user's attention is called requestApplicationWake but at the moment it does not work properly on devices (it shows a message but it doesn't vibrate the device) and you probably can't call it from within a watchface (haven't tried this)

In case you don't mind starting an app, the way out is to create an Application app type and implement something that looks like a clock face and doing your vibrations from there.