addHydrationData
write
raw milliliters, magnitude capped at 10000, negative values allowed; no delete endpoint exists, so **not safely round-trippable**
addHydrationData(valueInMl, when?, cdate?)| Parameter | Type | Optional | Description |
|---|---|---|---|
| valueInMl | number | no | |
| when | string (ISO date-time) | yes | A moment in time, ISO 8601, e.g. 2026-09-28T07:30:00 (local) or with Z/offset |
| cdate | string | yes | Calendar date, YYYY-MM-DD (UTC) |
In Claude this is the add_hydration_data tool.