openephemeris-mcp MCP Server

Model Context Protocol server for OpenEphemeris — typed astrology tools powered by the NASA JPL DE440 ephemeris. Zero hallucination on planetary positions, dates, and degrees. Covers 1,100 years of…

Local serverstdio

What is the openephemeris-mcp Server?

openephemeris-mcp is an MCP project maintained in the openephemeris/openephemeris-mcp repository. The maintainer describes its purpose as “Model Context Protocol server for OpenEphemeris — typed astrology tools powered by the NASA JPL DE440 ephemeris. Zero hallucination on planetary positions, dates, and degrees…”. Read the project documentation for the complete scope.

Installation

The documented npm package is @openephemeris/mcp-server. The configuration below comes from the maintainer’s example; adapt its paths and account values to your environment.

Configuration values

The example declares OPENEPHEMERIS_PROFILE, OPENEPHEMERIS_BACKEND_URL, OPENEPHEMERIS_API_KEY. Secret-looking values have been replaced with placeholders. Required and optional labels are shown only when the documentation states them.

Source

Project documentation · Repository · Discovery listing. This profile records the public documentation checked on 2026-10-08.

Recorded tools

Check the linked publisher documentation and your connected client's tool list. Names and availability can vary with the server version and account permissions.

Tool	What it does
Category	Tool
Synastry	ephemeris_synastry
Toolset	What it covers
astrology	Natal, transits, synastry, progressions, returns, relocation, dignities, midpoints, lots, fixed stars, composites
hd	Human Design charts, transits, connection charts, penta, bodygraph
bazi	Four Pillars, Ten Gods, element balance, luck pillars, compatibility
electional	Timing windows, angle crossings, stations, moment analysis
moon	Phases, void-of-course, eclipses
venus	Star points, phases, elongations, stations
acg	Astrocartography lines and hits
vedic	Jyotish Rashi chart

How to install the openephemeris-mcp Server

{
  "mcpServers": {
    "openephemeris": {
      "command": "npx",
      "args": [
        "-y",
        "@openephemeris/mcp-server"
      ],
      "env": {
        "OPENEPHEMERIS_PROFILE": "dev",
        "OPENEPHEMERIS_BACKEND_URL": "https://api.openephemeris.com",
        "OPENEPHEMERIS_API_KEY": "YOUR_OPENEPHEMERIS_API_KEY"
      }
    }
  }
}

From the project documentation. Replace placeholders and example paths before connecting.

Configuration

Variable	Description	Required
OPENEPHEMERIS_PROFILE	Declared in the maintainer’s client configuration.	Optional
OPENEPHEMERIS_BACKEND_URL	Declared in the maintainer’s client configuration.	Optional
OPENEPHEMERIS_API_KEY	Declared in the maintainer’s client configuration.	Check documentation