# 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 — check the specific planet in the response.
- **Timezone affects Western calculations more than Vedic.** Western natal charts must respect DST at time of birth. Use the timezone from the Location API, not the user's current clock.
- **Sign in horoscope path is lowercase.** `/astrology/horoscope/aries/daily`, never `/Aries/daily` or zodiac symbols.

## Vedic

- **Ayanamsa is server-side in Vedic.** LLMs default to tropical / Western math. Vedic endpoints apply sidereal Lahiri ayanamsa server-side. KP endpoints accept `kp-newcomb` (default), `kp-old`, `lahiri`, or `custom`. 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. Our split is authoritative — there are 30 distinct tithis in a lunar month.
- **Rahu and Ketu are shadow points, not planets.** They do not appear in a real ephemeris. Endpoints accept `nodeType` of `true-node` or `mean-node` to select which calculation to use.
- **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`.** Stay consistent with the field on the chart endpoint you actually called.

## Numerology

- **Numerology dates use three integers, not a date string.** `{ year: 1990, month: 1, day: 15 }`. A `birthDate` string fails validation.
- **`fullName` means birth-certificate name.** Nicknames or married names produce different numbers — every letter contributes.

## Tarot

- **Tarot reversals are a product choice.** `allowReversals: false` means no reversed cards in that draw, period. It is not cosmically meaningful — it is a config flag.
- **Card IDs are kebab-case slugs.** `the-fool`, `ace-of-cups`, `three-of-swords`. Not numeric like `major-01` or `cups-03`.

## Biorhythm

- **Seed-based daily endpoints are DETERMINISTIC per (seed, date) pair.** Same seed + same date = same reading. This is by design for push-notification consistency. Do not describe it as "cached" or retry on stale responses.

## I-Ching

- **Hexagram detail uses an integer path param 1-64.** Not the Chinese name (`qian`) or pinyin. `GET /iching/hexagrams/1`.
- **Daily and cast are different verbs.** Daily is POST, random cast is GET, seeded daily cast is POST. Do not unify them.

## Angel Numbers

- **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.