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No live ephemeris. The answers already exist. Ask a plain LLM what moon phase fell on a date, or what was retrograde, and you often get a confident guess — sometimes different the next time you ask. GEOMETRY replaces the guess with a lookup: sky dates computed offline with the standard Swiss Ephemeris (pyswisseph), stored once, returned identically on every call. Details: When it covers. Try it:
  1. Ask any chatbot: What was the moon phase on 1985-03-15, and which planets were retrograde that day?
  2. Connect https://mcp.geometry.app/mcp and ask the same question again
Same question, same model — the difference is the data layer. Use get_date; moon phase, season, and retrogrades are inside that payload. Caveat when an AI “saves” the JSON: the tool response is deterministic; if the model retypes the payload into a file, rare Unicode glyphs (e.g. alchemical_symbol on get_name) can flip to lookalike emoji while numbers and text stay correct. That is an LLM copy hazard — not GEOMETRY changing answers. See FAQ.