What it is
A single, unmissable stop
When the switch is set, every automated actor checks it and stands down before doing anything that changes the world. It fails safe — if in doubt, stop — rather than pressing on.
Why it exists
Reach demands an off-switch
Giving AI real reach demands an instant, total stop that does not rely on catching one specific action in time. Pull it and the whole system goes inert until a person resumes it deliberately.
Resuming is a decision
Never wears off
Resuming is not automatic: it takes a human action with a recorded reason. A halt is always something someone owns and ends — never a thing that quietly times out.