Western Astrology MCP Server by RoxyAPI

Generate natal chart - Birth chart calculator API with houses and aspects

post_astrology_natal_chart

Read-only

Calculate complete Western astrology natal chart (birth chart) with tropical zodiac. Returns all 14 celestial bodies (the 10 classical planets Sun through Pluto, the lunar nodes, Chiron, and Black Moon Lilith), 12 house cusps with customizable house systems (Placidus, Whole Sign, Equal, Koch), major and minor aspects, Ascendant, Midheaven, dominant elements and modalities. Perfect for astrology apps, birth chart generators, horoscope websites, and astrological consultation tools. Verified against NASA JPL Horizons.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`date`	Yes	Birth date in YYYY-MM-DD format. Determines planetary positions for the specific calendar day.
`lang`	No	Response language (BCP 47). Supported: en, tr, de, es, hi, pt, fr, ru, zh-Hans, zh-Hant. Defaults to en. Coverage varies by domain, and a field with no translation in the requested language returns English.	en
`time`	Yes	Birth time in 24-hour HH:MM:SS format. Determines the Ascendant (rising sign) and house cusps. Use 12:00:00 if unknown.
`compact`	No	Set true for the same data in a compact shape: arrays of same-shaped objects arrive columnar as {"__cols":[names],"__rows":[[values]]}. Lossless, typically 40 to 52 percent fewer tokens.
`latitude`	Yes	Birth location latitude in decimal degrees (-90 to 90). Positive = North, negative = South.
`nodeType`	No	Lunar node convention. "mean" is the smoothed average node, which always moves retrograde; "true" is the osculating node, which tracks the real perturbed node, oscillates up to about 1.5 degrees either side of the mean on a 173-day cycle, and can briefly turn direct. Neither is more correct and they almost always fall in the same sign. Applies to the North and South Node. True is the osculating node and the default, because it is what most Western chart software reports; mean is the smoothed node preferred by several evolutionary schools, so pass "mean" to match one. Nothing else in the chart changes, and the two agree on the sign except when the node sits within about 1.8 degrees of a cusp. Defaults to "true".	true
`timezone`	Yes	Timezone: IANA name (e.g. "America/New_York", "Europe/London") OR decimal hours from UTC (e.g. -5 for EST, 1 for CET). IANA strings are resolved to the DST-correct offset for the given date, so you can pass `cities[0].timezone` from /location/search directly.
`longitude`	Yes	Birth location longitude in decimal degrees (-180 to 180). Positive = East, negative = West.
`houseSystem`	No	House system for dividing the chart into 12 houses. Placidus (default) is most popular in Western astrology and time-sensitive. Whole Sign assigns one sign per house (simpler, ancient). Equal houses divide chart into 30° segments from Ascendant. Koch emphasizes houses in high latitudes.	placidus

TDQS

A3.9/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already confirm readOnly and not destructive, so the safety profile is covered. The description adds relevant method disclosures: it uses the tropical zodiac, supports customizable house systems, and is validated against NASA JPL Horizons. No contradiction with annotations exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and front-loads the core purpose: 'Calculate complete Western astrology natal chart'. The following clauses list output items in a structured, readable way. The 'Perfect for...' sentence is borderline marketing, but it does not repeat schema or waste much space.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Since there is no output schema, the description carries the burden of informing the agent what data to expect, and it does that by listing celestial bodies, house cusps, aspects, Ascendant, Midheaven, and dominants. Input requirements are fully covered by the schema. It omits possible error behavior or response structure details, but that is minor for a read-only computation API.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 100% description coverage across all 9 parameters, so the description does not need to duplicate parameter details. It adds context by naming the house-system choices, but it does not add meaning beyond what the schema already offers. Baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Uses a specific verb ('Calculate') and resource ('complete Western astrology natal chart'), and enumerates concrete output components: 14 celestial bodies, 12 house cusps, aspects, Ascendant, Midheaven, and dominants. This clearly distinguishes it from sibling tools like post_astrology_planets or post_astrology_aspects, which cover only subsets.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies this is the comprehensive natal-chart endpoint by saying 'complete' and listing full chart elements, but it never explicitly states when to use this tool versus specialized siblings like post_astrology_planets or post_astrology_houses. There is context, but no exclusions or alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All Western Astrology MCP Server by RoxyAPI tools Inspect

Try in Browser

RayrunBuild, deploy, and operate MCP servers without becoming an infrastructure team.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

TDQS

A3.8/5.0

Disambiguation3/5

Most tools are scoped to a clearly distinct domain—moon phases, houses, returns, fixed stars, astrocartography—but several pairs overlap, notably synastry vs. compatibility_score and transits vs. transit_aspects. The descriptions are long and do help an agent choose, but the boundaries are not always obvious at the name level.

Naming Consistency4/5

Every tool follows the same snake_case get_astrology_/post_astrology_ prefix pattern, making the group predictable and readable. However, collection endpoints like get_astrology_planet_meanings_id and get_astrology_signs_id awkwardly combine plural collection and singular id naming, and names like calendar_year_month depart from the cleaner resource+suffix pattern.

Tool Count2/5

With 38 tools, this is well over the 25+ threshold and feels heavy for an agent to traverse. While Western astrology is a broad domain, several near-duplicate endpoints, especially synastry/compatibility and transits/transit_aspects, could be consolidated into fewer, more scoped tools.

Completeness5/5

The toolset is comprehensive, covering natal charts, relationships, transits, returns, progressions, aspects, houses, relocation, and reference data. It includes enough specialized endpoints for both casual horoscope use and in-depth astrological analysis, with no obvious dead ends for the stated domain.

Resources

Need Help?