Open Ephemeris: MCP server, setup and security

What Open Ephemeris does

According to its repository: “Astrology from the NASA JPL DE440 ephemeris: natal, synastry, progressions, transit search, Human Design, Vedic, BaZi and astrocartography.”

An MCP server gives an AI agent extra tools it calls during the conversation: the agent reads their description, decides to use them and gets the result back. Open Ephemeris is listed under Other integrations, a category of 194 servers in the directory, where it ranks #183 by stars.

Topics declared by the repository: ai-agent, api, astro, astrology, astronomy, claude.

Installing and connecting Open Ephemeris

Distribution modes declared in the official MCP registry:

• remote server (streamable-http): you connect to it by URL, with nothing to install locally

Like any MCP server, you declare it in your client's configuration (Claude Desktop, Claude Code, Cursor, VS Code, Codex…): a name, the command that starts it or its URL, and any environment variables. The client then starts it and lists its tools. Project language: TypeScript. Listed systems: macOS, Windows, Linux.

Security: what to check

An MCP server runs code with the rights you give it, and the model reads its tool descriptions: a malicious or compromised server can hijack the agent. Read the code, or pick a maintained and widely used server, before connecting it.

None of the risk signals we track (system access, secrets, missing licence, abandonment) applies to Open Ephemeris. That does not replace reading the code.

Good practice: grant only the rights needed (least privilege), require human approval for irreversible actions, and run the AI agent security check.

Project activity and maintenance

Created on March 19, 2026, the openephemeris/openephemeris-MCP repository has 5 stars and 2 forks, with 0 open issues. It has more stars than 13% of the servers in the directory. It received changes this month. Version published in the registry: 4.24.2 (October 23, 2026).

Stars measure attention, not quality: a recent, heavily promoted project can collect them fast, while a useful but niche server will have few.