AstroWay Core astrology

Moon Void-of-Course

astroway_calendar_moon_voc

Read-onlyIdempotent

Find Moon void-of-course periods within a date range. The Moon is VOC from its last aspect until it enters the next sign.

[Group: Calendar & Cycles] [Cost: 10 credits (Tier 1)]

Input Schema

TableJSON Schema

Name	Required	Description
`date`	Yes
`time`	Yes
`fields`	No	Compact mode: comma-separated dotted paths to keep, relative to `data`, e.g. "planets.name,planets.longitude,houses.cusp". Omit for the whole response.
`timezone`	No	IANA zone name such as Europe/Kyiv, or auto to look the zone up from latitude and longitude. The server takes the offset that zone kept at this local date and time, summer time included, and uses it in place of timezoneOffset. A clock time that happened twice takes the first occurrence; one skipped when clocks went forward takes the offset from before the change. Abbreviations such as EST are refused. Before 1970 the tz database is not reliable for every place, so send timezoneOffset when the local clock is known.
`precision`	No	Compact mode: round fractional numbers to this many decimals. Longitudes carry 14 by default; 2 is finer than any chart is drawn.
`rangeDays`	No
`timezoneOffset`	No	Hours from UTC at the given moment, not minutes. Fractional zones are hours too: 5.5 for India, 5.75 for Nepal, -3.5 for Newfoundland. Defaults to 0, meaning UTC. Ignored when timezone is sent.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`periods`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 5, 2026

TDQS

B3/5.0

Behavior3/5

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

Annotations already declare this a safe, read-only, idempotent, non-destructive operation, so safety behavior is covered. The description adds the VOC definition and a credit cost tier, but says nothing about output shape, rate limits, or how periods are bounded/returned when none occur.

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?

Two tight sentences with the concept definition front-loaded, plus compact bracketed metadata for group and cost. No filler, though the group/cost tags are somewhat boilerplate.

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

Completeness3/5

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

An output schema exists, so return values need not be described, and annotations cover the safety profile. Still missing are sibling differentiation and any explanation of the three undescribed parameters, leaving the agent with questions before invocation.

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

Parameters2/5

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

Schema description coverage is only 57% — 'date', 'time', and 'rangeDays' have no schema descriptions at all. The description mentions only 'within a date range', which hints at rangeDays but does not explain the date/time format, the meaning of rangeDays, or how date+time+rangeDays combine. It fails to compensate for the coverage gap.

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

Purpose4/5

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

States a specific verb+resource ('Find Moon void-of-course periods') and even defines the domain concept (last aspect until next sign ingress). However, it does not differentiate this from closely related siblings such as astroway_calendar_moon_phase, astroway_calendar_lunar_calendar, or astroway_calendar_moon_aspects, which an agent could easily confuse it with.

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

Usage Guidelines2/5

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

No when-to-use / when-not-to-use guidance and no mention of any alternative tool. The sibling set contains at least three other Moon-calendar tools, so the absence of routing information is a real gap; usage must be inferred from the name alone.

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

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