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RoxyAPI Astrology MCP server

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Fixed stars and star conjunctions calculator - Regulus, Spica, Algol natal report

post_astrology_fixed_stars
Read-only

Calculate fixed-star positions for a birth chart and detect conjunctions with planets, Ascendant, and Midheaven to interpret Regulus, Spica, Aldebaran, Antares, and Algol contacts.

Instructions

Calculate the tropical zodiac positions of the major named fixed stars for any birth moment. Covers the four Royal stars and the fifteen Behenian stars, then detects conjunctions to the natal planets, Ascendant, and Midheaven. Each star returns its precessed ecliptic longitude, zodiac sign, visual magnitude, and traditional planetary nature, with a plain language interpretation for every conjunction inside the chosen orb. A focused tool for natal reports that weigh Regulus, Spica, Aldebaran, Antares, and Algol against the chart.

Input Schema

NameRequiredDescriptionDefault
orbNoConjunction orb in degrees, the maximum separation for a star to count as conjunct a chart point. Defaults to 1, maximum 3. Widen it to surface looser contacts or tighten it for only the closest hits.
dateYesBirth date in YYYY-MM-DD format. Determines planetary positions for the specific calendar day.
langNoResponse 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
timeYesBirth time in 24-hour HH:MM:SS format. Determines the Ascendant (rising sign) and house cusps. Use 12:00:00 if unknown.
compactNoSet 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.
latitudeYesBirth location latitude in decimal degrees (-90 to 90). Positive = North, negative = South.
nodeTypeNoLunar 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
timezoneYesTimezone: an IANA name (e.g. "America/New_York", "Europe/London", or `cities[0].timezone` from /location/search) or decimal hours from UTC (e.g. -5 for EST, 5.5 for IST). An IANA name is resolved to the offset in force at the given date and time.
longitudeYesBirth location longitude in decimal degrees (-180 to 180). Positive = East, negative = West.

Output Schema

NameRequiredDescriptionDefault
orbYes
starsYes
summaryYes
birthDetailsYes
conjunctionsYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed2 schema fields changedv1.1.2
    • changedInput schema / examples
      Previous value: -[
      -  {
      -    "date": "1990-07-15",
      -    "latitude": 40.7128,
      -    "longitude": -74.006,
      -    "time": "14:30:00",
      -    "timezone": -5
      -  }
      -]New value: +[
      +  {
      +    "date": "1990-07-15",
      +    "latitude": 40.7128,
      +    "longitude": -74.006,
      +    "time": "14:30:00",
      +    "timezone": "America/New_York"
      +  }
      +]
    • changedInput schema / properties / timezone / example
      Previous value: --5New value: +"America/New_York"
  2. First observedv0.1.0

TDQS

A4/5.0
Behavior4/5

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

Annotations already declare the read-only, non-destructive profile. The description adds real behavioral context beyond that: every returned star carries precessed longitude, sign, magnitude and planetary nature, and each conjunction inside 'the chosen orb' receives a plain-language interpretation. That tells the agent what is computed and how the orb affects output, though it doesn't discuss volume or edge cases.

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

Conciseness5/5

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

Four tight sentences: purpose, coverage/detection, return content, and audience. Front-loaded with the core action, no repetition of the title, and every sentence earns its place.

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?

With an output schema present, the description correctly avoids enumerating return fields in exhaustive detail while still summarizing its shape and the orb-driven interpretation. Safety is covered by annotations and inputs by the schema, so the description is complete enough; only the absence of any guidance about large conjunctions lists or performance keeps it from a 5.

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?

Schema description coverage is 100%, so the schema already documents all nine parameters thoroughly (orb, nodeType, timezone, compact, etc.). The description only alludes to 'the chosen orb' and 'the chart' without adding syntax or format detail beyond the schema, so 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?

States a specific verb and resource ('Calculate the tropical zodiac positions of the major named fixed stars') plus exact scope (four Royal stars, fifteen Behenian stars, conjunctions to planets/Ascendant/Midheaven). This clearly separates it from siblings like post_astrology_natal_chart, post_astrology_planets, or post_astrology_asteroids without the agent needing to open any schema.

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 closing sentence gives context ('a focused tool for natal reports that weigh Regulus, Spica, Aldebaran, Antares, and Algol'), implying when it is useful. However, it never states when to prefer this over the plain natal chart or planet tools, nor any exclusions or prerequisites, leaving usage to inference.

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