I've been reading charts for over 20 years, and I've spent plenty of that time frustrated by tools that guess at planetary positions or bury the math in jargon I have to translate for clients. OpenEphemeris solves that. It's built on NASA JPL data, is super precise, and helps create almost anything I can think of for client work, including customizable charts and reports.
What sold me is how much it covers in one place. Western, Vedic, BaZi, and Human Design, all through a single key, so I'm not stitching together five different libraries to serve clients across traditions. The free tier is generous enough to actually test the depth before committing, and the MCP connection means I can pull a chart straight into a Claude conversation without touching code- so easy to use!
For anyone building astrology or Human Design tools, or just tired of AI models hallucinating planetary positions, this is the real thing- check it out.
For anyone who wants to just try it instead of reading the pitch: openephemeris.com/astrology-mcp has a one-click "Add to Claude" that copies the connector URL and opens Claude's connector settings ready to paste.
Then ask something like "pull up my natal chart with Open Ephemeris — [your birth date, time, place]" and it renders right there, zoomable, with an "ask Claude to interpret this" button.
Also happy to dig into specifics if anyone's curious!