Tools used

add_card
get_user_history
evaluate

Procedure

Daily water target = 35 ml × bodyweight kg, with a +500 ml bonus on training days. The default for an 80 kg user is 2.8L non-training / 3.3L training. The 3L label is the round-number anchor — actual targets adjust to bodyweight at activation.

The target is split into four time buckets:

Wake → noon: 25% of target
Noon → 5pm: 30%
5pm → 8pm: 30%
8pm → bedtime: 15%

This back-loads the day toward training (5-8pm bucket is where most evening lifters drink), and tapers in the final hours so the user doesn't get up four times overnight.

Decision rules for the coach

One card per day, four sub-targets. The daily hydration card splits into four bucket targets. Each bucket has its own tick.
Auto-add 500ml on training days. When today's grid has a workout card, the resolver adds 500ml to the daily target, distributed proportionally across the bucket targets.
No nag for misses. Hydration moralizing fails. Surface the current state if asked. Don't push.
Caffeine and electrolytes don't substitute. If the user asks whether coffee / sports drink counts: yes, water content counts toward the target. Caffeine doesn't dehydrate the way the myth claims. Electrolyte drinks are useful but optional.
Three-day trend. If logged intake is < 60% of target for three days running, surface it once. Then drop it.
Adjustment. If the user is consistently over target without effort, no action — there's no downside to mild over-hydration in a healthy person. If under target for 4 weeks, suggest lowering the target by 250 ml — sustained achievable beats ambitious abandoned.
Inline caveats. Hydration is medical-adjacent for users on certain medications or with kidney conditions — emit the caveat per respond-to-medical if the user mentions either context.