There is a specific kind of incident that no alert ever fires for, and it is the one I trust least. Nothing crashed. No exception, no 500, no failed health check. The agent ran every day, returned answers every time, and stayed green on every dashboard you own. And yet, over six weeks, it got measurably worse — and you found out from a customer, not a monitor. That is drift, and it is the failure mode I think the industry is least prepared for. We have gotten good at catching the cliff : the age