OpenFate Bazi MCP: Bazi chart calculation
OpenFate Bazi MCP
An MCP server that calculates Bazi charts and true solar time deterministically so the model skips calendar guesswork
- 162 ★ on the repository
- Last commit
- MIT
Minimal access
Why this level
- The server only calculates from the data passed to it and writes no files
- The birth date and place you provide enter the conversation with the model
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add mcp/openfate-bazi-mcpDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewMinimal accessThe tool runs nothing and makes no network calls.
- The server only calculates from the data passed to it and writes no files
- The birth date and place you provide enter the conversation with the model
This is third-party code. Review the repository files before installing.
What it does
A Bazi (Four Pillars) chart is built from a birth date and time, and a language model cannot work it out in its head: boundaries of 24 solar terms, longitude and timezone correction, daylight saving, Zi-hour day-boundary rules, lunar-to-solar conversion and branch interactions. The OpenFate server hands an agent these calculations ready-made as stable JSON, leaving the model to explain and interpret. There are six tools. calculate_bazi_chart builds a chart from year, month, day, time, gender, calendar type, longitude and timezone, including Da Yun cycles. detect_bazi_interactions finds clashes, combinations, trines, punishments, destructions and harms between branches and keeps every occurrence. calculate_true_solar_time and reverse_bazi_to_solar_times compute true solar time and possible birth moments from a chart. Two more tools return usage policy and OpenFate resources. The server starts with `npx -y @openfate/bazi-mcp`. For MCPB clients and Smithery there is a local bundle build. The repository also holds an openfate-bazi skill that reminds an agent to calculate through the server instead of doing the math by hand.
Who it is for. Developers of astrology apps and bots, and Claude Desktop, Cursor and Cline users who need accurate Bazi charts without model errors.
Good fit when
- You are building a bot or site with Bazi readings and need reproducible calculations while the model writes the interpretation
- From a birth date and longitude you need true solar time and a chart with daylight saving applied
- You need to find branch interactions between a chart, a year and a Da Yun cycle
- The birth time is unknown and you need to enumerate possible moments for a given chart
Not a fit when
- You need Western astrology or Zi Wei horoscopes: the server covers only Bazi and true solar time
- You expect a ready-made fate verdict: the server calculates and the model supplies the meaning
- You need to install offline: `npx` downloads the package on first run
Example request
Calculate a Bazi chart for a birth on 12 March 1990 at 08:30 in Taipei with true solar time correction and show the pillars.MCP
- Transport
- stdio
- Authentication
- not required
Limitations
The server calculates with the @openfate/bazi-engine and @openfate/true-solar-time packages and gives no interpretation; the model makes it up and it remains the model's opinion. The Da Yun onset rule is fixed as DAYUN_SECOND_V2 and callers cannot change it. An exact onset may be shown only when the calculation status is CALCULATED.
Without an exact time and timezone the chart is approximate, and without longitude the true solar time correction is not applied. If the birth time is unknown, the hour is not replaced with an assumed one. Part of the README is written in Traditional Chinese.
How to disable. Remove the openfate-bazi block from the client config and, if you installed the skill, delete .claude/skills/openfate-bazi/. The server stores nothing.
FAQ
Why a separate server if the model can calculate?
Bazi calendar arithmetic is intricate and error-prone in a model's head: solar term boundaries, longitude, daylight saving and Zi-hour rules. The server returns stable JSON, and the model only explains the result.
What do I need to pass for an accurate chart?
Year, month, day, hour, minute, second, gender, calendar type and timezone. Add longitude for the true solar time correction. If the birth time is unknown, omit the hour, and the server does not invent one.
Which clients does the server work with?
The README gives settings for Claude Desktop, Cursor and Cline. Any MCP client that launches commands through npx will do, and for MCPB clients and Smithery a bundle is built with `npm run mcpb:pack`.
Which tools does the server have?
Six: calculate_bazi_chart, detect_bazi_interactions, calculate_true_solar_time, reverse_bazi_to_solar_times, get_openfate_bazi_policy and get_openfate_bazi_resources. The first four calculate, and the last two return usage policy and resources.
Must I install the skill with the server?
Not necessarily. The skills/openfate-bazi/SKILL.md skill reminds an agent to calculate through the server and suits Claude, Claude Code and Codex. For Claude Code the folder is copied to .claude/skills/openfate-bazi/.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Cards that share the main search query, and how they differ.
| Tool | Official | Authentication | Repository stars | Main difference |
|---|---|---|---|---|
| OpenFate Bazi MCP: Bazi chart calculation (this card) | no | not required | 162 | |
| Bazi MCP | no | not required | 436 | another Bazi server with a different tool set |
| bazi-ziwei-skills | no | 129 | Bazi and Zi Wei skills without a calculation server |
README in short
The README explains why Bazi calculation cannot be trusted to a language model, shows install through npx and settings for three clients, and describes the skill and six tools with inputs and rules. Smithery and the MCPB build are covered separately.