If you look into IPC primitives in each OS you can find goodies that do expose structured metadata about what interfaces are available and how they can be calle

If you look into IPC primitives in each OS you can find goodies that do expose structured metadata about what interfaces are available and how they can be called. D-Bus, sd-bus, COM, Binder, to name a few. It’s just that the tooling around it isn’t as easily exposed and they aren’t tailored for on-demand launch via command line. If the shell treated such as a more first class citizen, good results may come out. Another big problem is portability, if you designed your app with sdbus, it’s not going to work on a non systemd distro, even less on Windows. What’s needed is a standardized abstraction layer on top.