Operate doesn’t seem to be an ideal skill choice for a medieval setting, anyone have any ideas for a more suitable replacement?
Maybe “Control”? It’s also quite a neutral term and could also work for magical stuff. Or simply “Use”, “Handle”?
It may not be common but still useful.
You could use it to cover various mechanical devices like siege equipment, a draw bridge, wind/ water powered mills, cranes and lifts. Could also substitute for other skills such as driving a wagon or using a block and tackle to lift heavy loads.