About freebazi
freebazi is a local MCP server that calculates a Bazi chart from birth date, time, and place. It accounts for True Solar Time and historical daylight saving without an API key or network calls.
Key features
- 01Calculate Four Pillars and Day Master
- 02Analyze Ten Gods and Five Elements
- 03Apply True Solar Time correction
- 04Account for historical daylight saving
- 05Calculate luck pillars and yearly pillar
- 06Search city time-zone details
Use cases
- 01Generate a Bazi chart from birth details
- 02Compare alternative day-boundary rules
- 03Look up a city's longitude and time zone
MCP support
The MCP server exposes `compute_bazi_chart` and `search_cities` for chart calculation and city lookup. Calculations run locally without network calls.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
Tools
2Saved tool list · updated 2w ago
| Parameter | Type | Required | Description |
|---|---|---|---|
| day | integer | Yes | Birth day 1-31 |
| city | string | No | Birth city name, e.g. 'Taipei' or 'New York'. Resolved to longitude and IANA time zone for true solar time. Use search_cities first if unsure. |
| hour | integer | No | Birth hour 0-23 (local clock time as recorded) |
| year | integer | Yes | Birth year, e.g. 1990 |
| month | integer | Yes | Birth month 1-12 |
| gender | enum | Yes | Needed for the luck-pillar directionmale | female |
| minute | integer | No | Birth minute 0-59 |
| dayRule | enum | No | When a new day begins: 23:00 Zi hour (default) or midnightzi23 | midnight |
| yearRule | enum | No | Year boundary: Li Chun (default) or Lunar New Yearlichun | cny |
| longitude | number | No | Birth longitude in degrees East (negative = West). Use instead of city. |
| utcOffset | number | No | UTC offset in hours (e.g. 8 for China). Use with longitude when no city is given. |
| timeUnknown | boolean | No | True if the birth time is unknown; the hour pillar is then tentative |
| trueSolarTime | boolean | No | Apply true-solar-time correction (recommended) |
Details
From the project READMEfreebazi-mcp
English | 繁體中文
A Model Context Protocol server that computes a full Chinese Bazi (八字, Four Pillars of Destiny) chart from a birth date, time, and place.
It wraps the same calculation engine that powers freebazi.com: an offline engine that corrects for True Solar Time and historical daylight saving, and is cross-validated against established Bazi libraries. No API key, no network calls, everything runs locally.
What it returns
Give it a birth moment and a city, and compute_bazi_chart returns:
- The Four Pillars (Year, Month, Day, Hour), each as a Heavenly Stem and Earthly Branch
- Your Day Master (日干) and the Ten Gods (十神) of every character
- Hidden Stems (藏干), Na Yin (纳音), and the Twelve Growth Stages (十二长生)
- Five Elements distribution, both visible and including hidden stems
- Shen Sha (神煞) and branch relations (合冲刑害)
- Luck Pillars (大运) with the current period flagged, and the current year's pillar
- A link to the full interactive chart on freebazi.com
Install
Requires Node.js 18+.
Run directly with npx:
npx freebazi-mcp
Claude Desktop
Add to your claude_desktop_config.json:
{
"mcpServers": {
"freebazi": {
"command": "npx",
"args": ["-y", "freebazi-mcp"]
}
}
}
Other MCP clients (Cline, Continue, Cursor, etc.) take the same command / args.
Tools
compute_bazi_chart
Compute a full chart.
| Argument | Type | Notes |
|---|---|---|
year, month, day | number | Birth date |
hour, minute | number | Local clock time as recorded (omit if timeUnknown) |
gender | "male" | "female" | Needed for luck-pillar direction |
city | string | e.g. "Taipei", "New York". Resolved to longitude + time zone for True Solar Time |
longitude, utcOffset | number | Alternative to city |
timeUnknown | boolean | Hour pillar becomes tentative |
trueSolarTime | boolean | Default true |
dayRule | "zi23" | "midnight" | Day boundary, default 23:00 |
yearRule | "lichun" | "cny" | Year boundary, default Li Chun |
search_cities
Search about 490 major world cities by English or Chinese name. Returns each match's country, longitude, and IANA time zone, so you can pass an exact city to compute_bazi_chart.
Example
Compute the Bazi chart for someone born 15 June 1990, 9:30 AM, in New York.
The server resolves New York, applies True Solar Time (9:30 AM becomes 8:34 AM, 56 minutes earlier, which shifts the Hour pillar), and returns the four pillars 庚午 壬午 辛亥 壬辰 with a Xin (辛) yin Metal Day Master, all Ten Gods, elements, luck pillars, and more.
Accuracy and honesty
Solar-term boundaries are computed from the sun's apparent longitude with standard astronomical formulas, and time zones (including historical daylight saving) are resolved from the IANA database. The engine's four pillars match established libraries character for character across thousands of test charts.
Bazi is a traditional framework for reflection on temperament, tendencies, and timing. This tool describes a chart; it does not predict events.
Links
- Interactive calculator, guides, and full charts: freebazi.com
- What Bazi is and how to read it: freebazi.com/what-is-bazi
- How a Bazi chart is built: freebazi.com/bazi-chart
- The Five Elements (Wu Xing): freebazi.com/chinese-elements
- What a Day Master is: freebazi.com/day-master
- The Ten Gods explained: freebazi.com/ten-gods
Credits
City data from GeoNames (CC BY 4.0). Simplified to Traditional conversion via OpenCC.
License
MIT
繁體中文
一個 Model Context Protocol 伺服器,依出生的日期、時間與地點,排出完整的八字(四柱)命盤。
它使用與 freebazi.com 相同的排盤引擎:完全離線,會校正真太陽時與歷史上的日光節約時間,並和主流八字程式庫逐字對拍。無需 API key、不連網,全部在本機執行。
回傳內容
給它一個出生時刻與城市,compute_bazi_chart 會回傳:
- 四柱(年、月、日、時),每柱含天干與地支
- 日干與每個字的十神
- 藏干、納音、十二長生
- 五行分布(含藏干與不含藏干兩種)
- 神煞與地支刑沖合害
- 大運(標出當前運)與當年流年
- 一條連往 freebazi.com 完整互動命盤的連結
安裝
需要 Node.js 18+。直接以 npx 執行:
npx freebazi-mcp
Claude Desktop 及其他 MCP 客戶端(Cline、Continue、Cursor 等)的設定與上方英文段相同。
工具
compute_bazi_chart:排出完整命盤,參數見上方英文表格。search_cities:以中文或英文搜尋約 490 個世界主要城市,回傳國家、經度與 IANA 時區,方便傳給compute_bazi_chart。
連結
- 免費八字排盤與命盤:freebazi.com/zh-hant
- 英文版與說明頁:freebazi.com
八字是一套用於反思性格、傾向與時機的傳統框架。本工具只描述命盤,不預測具體事件。
Comments
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