True solar time is derived from longitude rather than assumed away, and it is also callable on its own, so a chart that disagrees with an ordinary clock-time tool can be explained instead of argued over. The reverse lookup is the unusual one: given only a four-pillar string, it returns the Gregorian datetimes that produce it — using clock-time pillars, without the location correction the forward path applies.
Six tools for deterministic Bazi calculation: a chart builder, a branch-interaction detector, a standalone true-solar-time conversion, and a reverse lookup from a four-pillar string to the datetimes that produce it.
- A chart with Day Master, Da Yun cycles and branch interactions, built from date, time, longitude and timezone
- True Solar Time correction that can be switched on or off, plus a DST offset and a dayBoundaryMode
- A calendarType and an isLeapMonth flag on the chart call
- Earthly Branch interactions on their own — clashes, combinations, trines, directionals, punishments, destructions and harms — for a natal chart, a synastry check or an annual trigger
- The true solar time calculation exposed separately, for explaining why an hour pillar differs from a clock-time tool
- A reverse lookup returning candidate Gregorian datetimes for a given four-pillar string, bounded by startYear, endYear and limit
- The calculation policy the server applies, and the canonical OpenFate URLs it points at
Node on your PATH. No account and no key. Longitude plus a timezone or timezoneId for the accuracy the chart tools describe.
One command — npx -y @openfate/bazi-mcp