Reminders are easy to ignore. Dismissing a notification costs nothing. So Hydration Hostage doesn't remind. It locks your Mac on a schedule and only unlocks when the camera (100% on-device, nothing uploaded) sees you actually take a sip.
Three escalating modes depending how much you trust yourself. One-time purchase, no subscription. The first of a series of apps that make you do the thing instead of nagging you to.
Reminders ask. Hydration Hostage enforces.