openephemeris

The most complete astronomical computation engine available as an MCP server. Open Ephemeris gives AI agents direct access to JPL DE440/DE441 ephemeris data — the same dataset used by NASA — for sub-arcsecond planetary precision and zero hallucination on dates, degrees, and positions. 50+ typed tools across every major astrological tradition: Western natal charts, transits, progressions, synastry, and composites; Human Design bodygraphs with gates, channels, and type analysis; Vedic/Jyotish with D-charts, dashas, and Ashtakavarga; Chinese BaZi Four Pillars; astrocartography power lines and local space; Venus Star Points; Arabic Parts; eclipse lookup; electional timing windows; and rendered chart wheels as native MCP images. All tools return structured JSON with format="llm" support for 50% smaller, token-efficient output. Free Explorer tier — no credit card required.