Find a city in the app's database by name (any of the app's six languages works) and get its coordinates, IANA timezone and elevation — feed those into the other tools.

Sunrise, sunset, solar noon, civil dawn/dusk, morning AND evening golden hour, and day length (with day-over-day trend) for a location and date. Handles midnight sun and polar night. Pure sun times — for vitamin D questions use the vitamin_d tools instead.

The solar vitamin D synthesis window for ONE specific day at a location, for a personal profile: when UV is strong enough (index ≥ 3), the best hour, the clear-sky minutes needed to reach the target IU, and (with atTime) the minutes at the specific hour the user plans to go out. Returns synthesisPossible=false when the sun never gets high enough that day. Only for single-day questions — for months, seasons or 'when during the year', call get_vitamin_d_year instead of calling this once per date.

The WHOLE YEAR of solar vitamin D for a location in a single call. monthsWithSun lists every month with at least one viable day (season edges count as partial months, see byMonth[].viableDays); solidMonths lists months where most days work; exactViableSpan gives the exact season boundaries; summary carries per-year aggregates for comparing places. Use this for any question about months, seasons, winter/summer or 'when during the year can I…' — never probe individual dates with get_vitamin_d_window for that.

Whether RIGHT NOW is a good moment for vitamin D synthesis at a location, using live Open-Meteo UV/cloud data when reachable (clear-sky model otherwise): current UV index, minutes needed now, and when today's window opens or closes.

Estimate a sun session's outcome: 'I was (or will be) out N minutes — how much vitamin D did I make?' plus 'how long before I'd burn?' for the profile. Takes a start time (defaults to the day's best hour) and session minutes; returns estimated IU (with the physiological cap), average UV and clear-sky minutes-to-sunburn. Use for any 'how much did I get / can I get in X minutes' or 'how long without burning' question.

The signed-in user's saved Vitamin D profile: skin type, exposed-skin default, age, target IU and their current city. Requires connecting with OAuth (scope profile:read). Call this FIRST for any personal question, then pass its values to the public tools instead of asking the user.

The signed-in user's current city and favorite cities with coordinates and timezones, ready to feed into the public tools. Requires OAuth (scope profile:read).

The signed-in user's sun history from the app's calendar: which recent days had viable sun, which they confirmed going outside, and their current streak. Requires OAuth (scope history:read).

Marks a day as sun-confirmed in the signed-in user's history calendar — use when the user says they went (or will have gone) outside for their sun. Defaults to today. Requires OAuth (scope history:write).