> Hex will let you know when he is bored by interrupting your work with a note in your terminal

Cats routinely initiate attention grabbing denial of service attacks by blocking access to hardware so this needs proper emulation to increase the realism. I have a few recommendations:

Mouse trapping - when cat pops up the mouse cursor should be limited in motion as if you turned the sensitivity down to near 0. This emulates a cat who lies directly on top of your mousing hand while using said mouse.

Keyboard injection - after cat pops up all further typing results in cat-on-a-keyboard output. This emulates a cat sitting or walking across your keyboard.

Screen jacking - The screen has a cat shaped blank spot that obscures most of your working environment. This can also be paired with cat-on-a-keyboard typing. Emulates cat sitting in front of monitor, likely on top of keyboard.

Once hardware denial fails they move on to destroying your personal items:

destruction of personal items - USB solenoids strategically placed behind any object that you either a. cherish or b. do not want spilled. "That nice book you were just admiring - now it has coffee all over it because I am need something."

I could go on but these are a good starting point.