Is it possible to execute command on focus move to a window with specific class/title?

[kimifish]

I need quite specific keyboard and power settings in certain applications. Can I automatically run shell script with one argument when moving the focus to a window with a certain class and a title and run it again, with a different arg, with focus loss?

[orestisfl]

Yes, check the i3 IPC interface: https://i3wm.org/docs/ipc.html

You can subscribe and react to window focus events