Tracks daily caffeine intake from beverages, models residual caffeine using half-life decay (t1/2=5.7h), and predicts safe sleep time. Use when the user logs coffee, tea, or energy drink consumption, asks about caffeine levels, or wants to know when it is safe to sleep.
Records daily caffeine intake, estimates residual body caffeine via first-order elimination kinetics (half-life 5.7 h), predicts safe sleep time, and provides daily intake summaries with health alerts.
Extract and record beverage type, caffeine content (mg), and intake time from natural-language input.
Record fields: intake time (HH:MM 24h), beverage name, caffeine amount (mg), optional notes (e.g. "double shot").
Use a first-order elimination model to compute current residual caffeine.
Core formula:
C(t) = C0 * 0.5^(t / 5.7)
C(t) -- residual after t hours (mg)C0 -- initial dose (mg)5.7 -- mean half-life in hours (healthy adults)Cumulative calculation (multiple doses in one day):
Total_residual = SUM[ dose_i * 0.5^((now - time_i) / 5.7) ] for all i
Solve for the time when total residual decays below the safe-sleep threshold (50 mg).
hours_until_safe = 5.7 * log2(C_current / 50)
For full accuracy, simulate cumulative decay from all active doses until total < 50 mg.
Statistics: total intake (mg), number of beverages, current residual (mg), estimated safe sleep time.
Alert rules:
| Condition | Alert |
|---|---|
| Daily total > 400 mg | [Warning] Daily caffeine exceeds 400 mg (FDA adult daily limit) |
| Intake after 18:00 AND residual > 100 mg | [Warning] Evening caffeine intake; high residual at bedtime may impair sleep |
| Single dose > 200 mg | [Notice] High single dose; consider splitting intake |
| Beverage | Default (mg) | Notes |
|---|---|---|
| Espresso | 63 | per shot (30 ml) |
| Drip Coffee | 95 | per cup (240 ml) |
| Latte | 80 | single shot + milk |
| Cappuccino | 80 | single shot |
| Cold Brew | 120 | per cup (240 ml) |
| Green Tea | 30 | per cup (240 ml) |
| Black Tea | 47 | per cup (240 ml) |
| Matcha | 70 | per serving (2 g powder) |
| Cola | 34 | per can (355 ml) |
| Energy Drink | 80 | per can (250 ml) |
| Decaf Coffee | 3 | per cup (240 ml) |
| Double Espresso | 126 | 2 shots |
| Dark Chocolate | 20 | per 30 g |
Size modifiers: "large" = default x 1.5; "two cups" = default x 2; explicit mg from user overrides lookup.
Natural language, e.g.:
## Caffeine Intake [caffeine-tracker · HH:MM]
Recorded: Latte 80 mg (14:30)
### Current Status
- Today's intake: 230 mg / 400 mg
- Current residual: ~185 mg
- Safe sleep time: 22:45
### Today's Detail
| Time | Beverage | Dose (mg) | Residual (mg) |
|------|----------|-----------|---------------|
| 08:30 | Drip Coffee | 95 | ~42 |
| 11:00 | Green Tea | 30 | ~18 |
| 14:30 | Latte | 80 | ~125 |
| **Total** | | **230** | **~185** |
## Caffeine Status [caffeine-tracker · HH:MM]
### Current Status
- Today's intake: 230 mg / 400 mg
- Current residual: ~120 mg
- Safe sleep time: 22:15
### Today's Detail
| Time | Beverage | Dose (mg) | Residual (mg) |
|------|----------|-----------|---------------|
| 08:30 | Drip Coffee | 95 | ~28 |
| 11:00 | Green Tea | 30 | ~12 |
| 14:30 | Latte | 80 | ~80 |
| **Total** | | **230** | **~120** |
memory/health/daily/YYYY-MM-DD.md)Update the ## Caffeine [caffeine-tracker · HH:MM] section:
## Caffeine [caffeine-tracker · HH:MM]
- Residual: ~185mg
- Safe to sleep: 22:45
- Today's intake: Americano 95mg (08:30), Green tea 30mg (11:00), Latte 80mg (14:30)
- Total: 230mg / 400mg
memory/health/items/caffeine.md)---