A four-step saga is: reserve inventory (compensatable), charge the card (compensatable), send a "your order shipped" push notification (no compensation possible), create the order record (compensatable). Where does the notification actually belong in the sequence, and what does "the pivot" mean here?

The rule is simple once stated: a step with no compensation has to go last, after every step that could still fail and be undone, because once it runs there's no way back from it. So the notification goes at the very end — reserve, charge, create order, then notify — never before create order, even though 'notify the customer their order shipped' reads naturally as something that might belong near the end of a business narrative anyway (it does, but for a structural reason, not just a narrative one). The pivot is whichever compensatable step, once it succeeds, the saga is committed to finishing forward from — here that's naturally 'create order': everything before it (reserve, charge) is still compensatable if something later fails, but once the order record exists, there's genuinely nothing left worth compensating the charge or the reservation for, so the saga is going to push forward to the notification no matter what. Steps after the pivot (the notification here) are called retriable rather than compensatable, because the design has to guarantee they'll essentially always eventually succeed — since there's no going back to undo anything before them anymore.