Ephemeris Mcp

io.github.scottchronicityPublished by GitHub account scottchronicityv1.2.0Updated Oct 24, 2026

Precision astronomical ephemeris and planetary positions via the Swiss Ephemeris.

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Overview

AI-generated overview

A local MCP server that gives an assistant precision astronomical ephemeris data, computing planetary positions and chart angles via the Swiss Ephemeris.

What you can do
Compute planetary positions: return Tropical Zodiac positions for the Sun, Moon and planets, including sign, degrees, direct or retrograde motion, speed and declination for a given ISO-8601 time and observer coordinates, plus Ascendant and Midheaven chart angles.
When to use it
Useful when you want an assistant to calculate or discuss astronomical and astrological positions for a specific date, time and location, such as chart angles or planetary motion, without leaving the chat.
Requirements
Runs as a local process over stdio, started on demand by the MCP client. Install from PyPI with uvx or pip (Python), or run the published Docker image. No accounts, API keys or environment variables are declared.
Before you install
Observer latitude and longitude default to Detroit, Michigan, so pass explicit coordinates for other locations. Results are computed positions from the Swiss Ephemeris; verify them before relying on them for anything consequential.

Installation

In SourceWeft

  1. Open Ephemeris Mcp in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

Ephemeris MCP 🌌

[PyPI version] [CI] [License: AGPL v3]

mcp-name: io.github.scottchronicity/ephemeris-mcp

Precision Astronomical Ephemeris for AI Agents.

Ephemeris MCP is a Model Context Protocol (MCP) server that provides AI agents with precision planetary positions using the Swiss Ephemeris.

To use this in Claude Desktop, add this to your claude_desktop_config.json:

json
"mcpServers": {  "ephemeris": {    "command": "uvx",    "args": ["ephemeris-mcp"]  }}

Quick Start

Install via PyPI (Recommended)

bash
# Install with uvx (recommended - fast & isolated, no local install needed)uvx ephemeris-mcp
# Or install globally with pippip install ephemeris-mcppython -m ephemeris_mcp

Register with MCP Clients

Add to your MCP client configuration (client will start server on-demand):

Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

json
{  "mcpServers": {    "ephemeris-mcp": {      "command": "uvx",      "args": ["ephemeris-mcp"]    }  }}

VS Code/Cursor/Windsurf (Cline MCP settings):

json
{  "mcpServers": {    "ephemeris-mcp": {      "command": "uvx",      "args": ["ephemeris-mcp"]    }  }}

The client starts the server process automatically, communicates over stdin/stdout, then terminates it when done.

Alternative: Docker

If you prefer container isolation:

bash
# Pull latest imagedocker pull ghcr.io/scottchronicity/ephemeris-mcp:latest
# Test itdocker run --rm -i ghcr.io/scottchronicity/ephemeris-mcp:latest

Configure MCP client with Docker:

json
{  "mcpServers": {    "ephemeris-mcp": {      "command": "docker",      "args": ["run", "--rm", "-i", "ghcr.io/scottchronicity/ephemeris-mcp:latest"]    }  }}

Local Development

bash
# Clone and installgit clone https://github.com/scottchronicity/ephemeris-mcp.gitcd ephemeris-mcpuv sync
# Run testsmake test
# Run locallyuv run ephemeris-mcp
# Test the engine directlymake validate-happycase

Available Tools

get_planetary_positions

Returns precise Tropical Zodiac positions for all planets, Sun, Moon, and chart angles.

Parameters:

  • iso_time (string): ISO-8601 timestamp (e.g., "2025-12-16T15:28:00Z")
  • latitude (float): Observer latitude (default: 42.3314 - Detroit, MI)
  • longitude (float): Observer longitude (default: -83.0458 - Detroit, MI)

Returns:

  • bodies: Sun, Moon, planets with sign, degrees, motion (direct/retrograde), speed, declination
  • houses: Ascendant (ASC) and Midheaven (MC) with sign and degrees

Architecture

See docs/adr/ for architectural decisions:

  • ADR 001: Geocentric Tropical Ecliptic coordinates specification
  • ADR 002: Semantic versioning with Conventional Commits
  • ADR 003: CI/CD pipeline architecture

License

AGPLv3

Source: README.md at commit 2f9055c

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.2.0LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts