Get the moon phase, illumination, moon sign and next full/new moon for any date (1900–2100). Optionally pass latitude/longitude to also get moonrise and moonset times (UTC).
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | Date as YYYY-MM-DD or ISO 8601. Omit for now. | |
| latitude | No | Optional, -90..90. Requires longitude. | |
| longitude | No | Optional, -180..180. Requires latitude. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses that latitude/longitude are needed for moonrise/moonset and that times are in UTC. However, it omits the default behavior when 'date' is omitted (per schema 'Omit for now') and does not clarify time zone interpretation for the input date or return format details. This leaves some behavioral gaps.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two concise sentences, front-loaded with the primary purpose, followed by the optional enhancement. No redundant or filler content; every phrase earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The tool is simple (3 optional params, no output schema) and the description covers its core outputs and the optional parameter behavior. It misses the default-date behavior and time zone details, but is otherwise adequate for selecting and invoking the tool correctly.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions cover all parameters (100%), so baseline is 3. The description adds meaningful context by explaining that latitude/longitude enable moonrise/moonset calculations and that the date is restricted to 1900–2100, which goes beyond the schema's parameter-level descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's function: getting moon phase, illumination, moon sign, and next full/new moon for a specified date. This is a specific verb+resource (Get moon phase) and distinguishes from sibling tools (list_full_moons, list_new_moons) which list events rather than provide phase details for a date.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides clear context for usage: it works for any date within 1900–2100, and optionally requires latitude/longitude to get moonrise/moonset times. However, it does not explicitly state when to prefer this over the sibling list tools, though the implied difference is evident from their names.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool has a distinct purpose: get_moon_phase for a single date, list_full_moons for full moons in a year, and list_new_moons for new moons in a year. There is no overlap in functionality, making selection unambiguous.
All tool names follow a consistent verb_noun pattern: get_moon_phase, list_full_moons, list_new_moons. The naming style is uniform and predictable.
With only 3 tools, the server is well-scoped for its domain of moon phase information. Each tool covers a core need (single-date phase, full moons, new moons) without unnecessary redundancy.
The set lacks a tool to list all moon phases for a year or month; only full and new moons are listed. This is a notable gap because agents cannot efficiently obtain a complete phase calendar without repeatedly calling get_moon_phase.
