Zodiac Compatibility

Find a Moon sign

find_moon_sign

Read-onlyIdempotent

Returns the Moon's tropical zodiac sign for a birth date, with its degree when a birth time is given. Without a time it returns every sign the Moon visited that local date and when it changed sign.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "birthDate": "<birthDate>"
    },
    "name": "find_moon_sign"
  }
}

Input Schema

Name	Required	Description
`place`	No	A city from the website's list of 67 places, in any letter case, such as London, New York, Tokyo, Sydney or Mumbai.
`timeZone`	No	An IANA time zone name such as Europe/London, used instead of a city's zone.
`birthDate`	Yes	Birth date as YYYY-MM-DD, from 1900 to 2100.
`birthTime`	No	Local birth time as HH:MM on a 24-hour clock.

Output Schema

Name	Required	Description	Default
`item`	Yes
`view`	Yes
`request`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 11, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety bar is low. The description adds genuine behavioral detail beyond them: precision improves with a time, and without one the result expands to every sign the Moon touched that local date and the changeover time.

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?

Two sentences, zero filler, with the primary behavior front-loaded and the no-time fallback in the second sentence. Nothing redundant or padded.

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 and annotations covering safety, the description only needed to characterize the two response modes, which it does. A note on what the 'local date' depends on (place vs timeZone) would close the remaining gap.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning by tying birthTime to a distinct output shape (degree vs multi-sign enumeration). It does not explain place vs timeZone interaction, but that is already documented in the schema.

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?

The description names the specific resource and output: the Moon's tropical zodiac sign for a birth date, plus its degree when a time is supplied. The word 'Moon' implicitly separates it from the find_sun_sign and find_rising_sign siblings, though it never says so explicitly.

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?

It clearly explains the two operating modes driven by whether birthTime is present, which is real usage guidance. However, it never states when an agent should pick this tool over the sibling sign tools (sun, rising, venus), leaving that routing to inference.

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

All Zodiac Compatibility tools Inspect

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