Astrology Server

An MCP (Model Context Protocol) server that provides astrological birth chart calculations. Given a birth date, time, and location, it calculates planetary positions, house placements, aspects, and key chart points.

Features

• Complete Birth Chart Calculation: Calculates positions for Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, Chiron, and Lunar Nodes
• House System Support: Placidus, Koch, Whole Sign, Equal, Campanus, Regiomontanus, and Topocentric house systems
• Zodiac Systems: Both Tropical and Sidereal zodiac support
• Aspect Calculation: Major aspects (conjunction, opposition, trine, square, sextile) and minor aspects
• Key Chart Points: Ascendant (Rising Sign), Midheaven (MC), and Chart Ruler identification
• The Big Three: Highlights Sun Sign, Moon Sign, and Rising Sign

Installation

npm install
npm run build

Usage

With Claude Desktop

Add to your Claude Desktop configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "astrology": {
      "command": "node",
      "args": ["/path/to/astro-mcp/build/index.js"]
    }
  }
}

Tools Available

get_birth_chart

Calculate a complete natal birth chart.

Parameters:

• year (number): Birth year (1900-2100)
• month (number): Birth month (1-12)
• day (number): Birth day (1-31)
• hour (number): Birth hour in 24-hour format (0-23)
• minute (number): Birth minute (0-59)
• latitude (number): Birth location latitude (-90 to 90)
• longitude (number): Birth location longitude (-180 to 180)
• houseSystem (string, optional): House system to use (default: "placidus")
• zodiac (string, optional): Zodiac system (default: "tropical")

Example:

{
  "year": 1990,
  "month": 6,
  "day": 15,
  "hour": 14,
  "minute": 30,
  "latitude": 40.7128,
  "longitude": -74.006
}

get_zodiac_info

Get detailed information about a zodiac sign.

Parameters:

• sign (string): One of: aries, taurus, gemini, cancer, leo, virgo, libra, scorpio, sagittarius, capricorn, aquarius, pisces

get_aspect_info

Get detailed information about astrological aspects.

Parameters:

• aspect (string): One of: conjunction, opposition, trine, square, sextile, quincunx, quintile, semisextile, semisquare, sesquiquadrate

Chart Components

Planets/Points (The Actors)

• Sun: Core identity, ego, purpose
• Moon: Emotions, nurturing, inner world
• Mercury: Communication, thought processes
• Venus: Love, relationships, values
• Mars: Action, energy, drive
• Jupiter: Growth, luck, expansion
• Saturn: Discipline, challenges, structure
• Uranus: Innovation, rebellion, sudden change
• Neptune: Dreams, intuition, spirituality
• Pluto: Transformation, power, rebirth
• North Node: Life purpose, destiny
• South Node: Past karma, innate talents
• Chiron: Healing, wounds, wisdom

Houses (Life Areas)

1. Personality, appearance (Ascendant)
2. Finances, self-esteem
3. Communication, siblings
4. Home, family
5. Creativity, romance
6. Health, daily work
7. Partnerships, marriage
8. Transformation, shared resources
9. Higher education, philosophy
10. Career, reputation (Midheaven)
11. Friendships, community
12. Subconscious, spirituality

Aspects (Planetary Relationships)

• Conjunction (0°): Fusion of energies
• Opposition (180°): Tension, balance needed
• Trine (120°): Harmony, flow
• Square (90°): Challenge, growth through friction
• Sextile (60°): Opportunity, cooperation

Dependencies

• @modelcontextprotocol/sdk: MCP SDK for server implementation
• circular-natal-horoscope-js: Astrological calculations library
• zod: Schema validation

License

ISC