Western Compatibility
asterwise_get_western_compatibility
Overall compatibility score (0–100) between two natal charts. Scores element affinity, synastry aspects between personal planets (Sun, Moon, Venus, Mars), and Sun/Moon/rising sign comparisons.
Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
person1 | object | yes | Birth data for Western astrology tools (tropical zodiac). Fields: date, time, lat, lon, person_name, timezone, house_system |
person2 | object | yes | Birth data for Western astrology tools (tropical zodiac). Fields: date, time, lat, lon, person_name, timezone, house_system |
response_format | enum: markdown, json | no |
What it covers
Weighted scoring model combining elemental harmony, personal-planet synastry hits, and luminaries/rising affinity labels. Higher score = more harmonious synergy — interpret relatively, not as fate.
Workflow
BEFORE: asterwise_get_western_natal per person optional.
AFTER: asterwise_get_western_synastry — drill into raw aspects if score needs detail.
Input
person1, person2 — WesternBirthData each.
Output contract
data.overall_score (int 0-100)
data.element_score (int 0-100)
data.aspect_score (int 0-100)
data.sun_sign_affinity, data.moon_sign_affinity, data.rising_sign_affinity — 'harmonious'|'neutral'|'challenging'
data.person1_sun, data.person2_sun, data.person1_moon, data.person2_moon
data.key_aspects[] — aspects between personal planets
Response format
response_format=json serialises the complete response as indented JSON.
response_format=markdown renders the same data as a human-readable report.
Both modes return identical underlying data.
Compute class
MEDIUM_COMPUTE
Errors
INVALID_PARAMS (local): WesternBirthData validation failures.
INTERNAL_ERROR: Any upstream API failure or timeout → MCP INTERNAL_ERROR
Edge cases:
Score reflects multiple weighted factors. Use for relative comparison between charts, not as an absolute outcome predictor.
Do not confuse with
asterwise_get_western_synastry — raw aspects, no score.
asterwise_get_western_zodiac_compatibility — sign-only, no birth data.
Connect
Remote MCP endpoint: https://mcp.asterwise.com/mcp. Authenticate with Authorization: Bearer <API key> or OAuth. See the MCP setup guide.