Unix philosophy also seems to assume that the users and developers of the beep software are different people with different priorities than the calendar app people. I think the crux of this discussion is whether you are in one of these camps or you're trying to sell a holistic solution to their beeping calendar needs. The latter will never be done because holism means being tenderly connected to a changing world.

But in terms of pipes, it seems like the 2010s version would probably be JSON over HTTP.