The job: deciding when to order, not how much
How it is done today
In most small retail and distribution businesses, reordering is triggered by eyesight. Someone notices a gap on the shelf, or a customer asks for something and the answer is no, and a purchase order follows. By then the supplier lead time has not started, so the shortage lasts at least as long as the delivery takes.
A reorder alerter moves the trigger earlier by a fixed, calculated amount. It does not decide quantity, it does not forecast the season, and it does not replace a buyer. It answers one question per SKU: has cover fallen to the point where an order placed today still arrives before the shelf is empty.