Staff mode

/staff saves inventory, armour, level, health, game mode, flight, effects and location to modo-staff/<uuid>.yml before touching anything, and gives it all back when you leave. If the server crashes, it is restored on the next join.

Hotbar tools: compass (left click pass through walls, right click go where you look), inspector, CPS test, knockback test, freeze, player menu, fly speed, random teleport (no repeats) and vanish. No damage, no hunger, no building or dropping/picking up items (configurable), and chests open silently.