calculate_bazi_chart
Calculate a deterministic OpenFate Bazi/Four Pillars chart with True Solar Time correction, Day Master, Da Yun cycles, and branch interactions. For best accuracy, pass longitude plus timezone or timezoneId.
LABSCO SUMMARY
The hour pillar stops being whatever the wall clock said.
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.
What it is
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.
What you get
- 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
Requirements
Node on your PATH. No account and no key. Longitude plus a timezone or timezoneId for the accuracy the chart tools describe.
Setup effort
One command — npx -y @openfate/bazi-mcp
USE CASES
01
Casting a chart from a birth record
Date, time, longitude and timezone go in; the chart comes back with Day Master, Da Yun cycles and branch interactions already resolved, with true solar time applied unless you switch it off.
02
Checking what a given year triggers in a chart
Pass the four natal branches and the annual branch and the interactions come back typed — clashes, combinations, trines, directionals, punishments, destructions, harms — rather than as prose to interpret.
03
Recovering a birth time from a chart you were sent
When all you have is a four-pillar string from a screenshot, the reverse lookup returns the Gregorian datetimes that produce it, bounded by a year range and a result limit.
6 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
calculate_true_solar_time
Calculate OpenFate True Solar Time from civil birth time, longitude, timezone, and optional DST offset. Use this when explaining why the hour pillar may differ from ordinary clock-time tools.
detect_bazi_interactions
Detect deterministic Earthly Branch interactions for natal charts, synastry checks, annual triggers, or target-branch comparison. Covers clashes, combinations, trines, directionals, punishments, destructions, and harms.
get_openfate_bazi_policy
Return OpenFate calculation policy and LLM guidance for Bazi chart calls.
get_openfate_bazi_resources
Return canonical OpenFate URLs for charting, readings, compatibility, wealth, true solar time, and AI crawler metadata.
reverse_bazi_to_solar_times
Find possible Gregorian datetimes that produce a given four-pillar Bazi string. This is useful when a user only has a Bazi chart or screenshot. This lookup uses clock-time pillars without location-based true solar correction.
BEFORE YOU INSTALL
What to know first
Tools you get
6 tools when we connected.
Requires
npx on PATH
Where it runs
All 3 documented clients run the server on your machine.
CONTEXT COST
Light Standing cost
Rated by the size of the 6 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Server setup
TERMINAL
npx -y @openfate/bazi-mcpMCP Clients
Claude Desktop, Cursor
JSON
{
"mcpServers": {
"openfate-bazi": {
"command": "npx",
"args": [
"-y",
"@openfate/bazi-mcp"
]
}
}
}Cline
CLINE · JSON
{
"mcpServers": {
"openfate-bazi": {
"command": "npx",
"args": [
"-y",
"@openfate/bazi-mcp"
],
"disabled": false
}
}
}
