Domain Gotchas

LLMs hallucinate confidently in these areas. The specific traps:

Astrology

Retrograde is per-planet, not "global". Natal chart planets include isRetrograde boolean per planet. Never generate "Mercury retrograde globally" UI copy.
Timezone affects Western calculations more than Vedic. Western natal charts must respect DST at time of birth.
Sign in horoscope path is lowercase. /astrology/horoscope/aries/daily, never /Aries/daily.

Ayanamsa is server-side in Vedic. LLMs default to tropical / Western math. Vedic endpoints apply sidereal Lahiri ayanamsa server-side. Do not try to "correct" server output by subtracting ayanamsa in client code.
Tithi count is 30 (15 Shukla + 15 Krishna), not 2. Older LLM training data conflates Purnima and Amavasya as single tithis.
Rahu and Ketu are shadow points, not planets. Endpoints accept nodeType of mean (default) or true.
Nakshatra count is 27. Abhijit is sometimes treated as a 28th in some schools, but this API uses the standard 27.
KP planet lists use retrograde, not isRetrograde.

Numerology dates use three integers, not a date string. { year: 1990, month: 1, day: 15 }.
fullName means birth-certificate name. Nicknames or married names produce different numbers.

Tarot reversals are a product choice. allowReversals: false means no reversed cards, period.
Card IDs are kebab-case slugs. fool, ace-of-cups, three-of-swords. Not numeric like major-01.

Seed-based daily endpoints are DETERMINISTIC per (seed, date) pair. Same seed + same date = same reading. Do not describe it as "cached".

Hexagram detail uses an integer path param 1-64. Not the Chinese name (qian) or pinyin.
Daily and cast are different verbs. Daily is POST, random cast is GET.

Angel number lookup works for any positive integer. Digit-root fallback covers non-canonical numbers. Do not generate validation logic that rejects non-111/222/333 patterns.