Authoritative time intelligence — current time in 597 timezones, sunrise/sunset/twilight times by location (US Naval Observatory), and moon phase calendar. Essential for scientific, agricultural, and scheduling agents.
Scored across 3 tools
Each tool targets a clearly distinct aspect: astronomical events (sunrise/sunset/moonrise/moonset), current time in any timezone, and moon phases. There is no overlap in their outputs.
All tools follow a consistent 'get_' prefix with a specific noun indicating the data returned (astronomy, current_time, moon_phases). This pattern is predictable and easy to understand.
With only 3 tools, the server is well-scoped for its purpose—covering current time, astronomical events, and moon phases. Each tool is necessary and none seem redundant.
The server covers core time and astronomy needs: current time in any timezone, daily astronomical events, and moon phase information. Minor gaps exist (e.g., historical time data or planetary positions), but the surface is reasonably complete for common queries.
Get sunrise, sunset, and twilight times for any location using US Naval Observatory data. Also returns moonrise and moonset.
| Name | Required | Description | Default |
|---|---|---|---|
| tz | No | UTC offset in hours (e.g. -5 for EST, 1 for CET). Default: 0 (UTC) | |
| lat | No | Latitude (default: 40.7128 — New York City) | |
| lon | No | Longitude (default: -74.0060 — New York City) | |
| date | No | Date in YYYY-MM-DD format (default: today) |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It mentions the data source (US Naval Observatory) but does not disclose rate limits, accuracy, or how time zone handling affects results. Adequate but not comprehensive.
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 clear sentences with no wasted words. Could be slightly more structured with a note on return format, but efficient.
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?
No output schema exists, but the description does not explain the return format or possible errors. For a tool with 4 parameters and no annotations, this is incomplete.
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 coverage is 100% with all parameters described. The description adds no additional meaning beyond the schema, so baseline of 3 is appropriate.
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 verb 'Get' and the resource 'sunrise, sunset, and twilight times' and also mentions moonrise/moonset. It distinguishes from sibling tools like 'get_current_time' (just time) and 'get_moon_phases' (phases only).
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?
No guidance is provided on when to use this tool versus alternatives. It does not mention context or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Get the current time in any timezone. Returns local datetime, UTC datetime, unix epoch, UTC offset, DST status, day of week, day of year, and week number.
| Name | Required | Description | Default |
|---|---|---|---|
| format | No | Response format: iso (datetime only), unix (epoch only), both (default) | both |
| timezone | No | IANA timezone name (e.g. America/New_York, Europe/London, Asia/Tokyo). Defaults to UTC. | UTC |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It details the return fields (datetimes, unix, offset, DST, etc.) but does not mention potential issues like timezone validation or rate limits. Still, it gives good transparency for a simple read operation.
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?
The description is a single, efficient sentence followed by a clear list of return fields. No fluff; every part adds value.
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?
No output schema exists, but the description thoroughly enumerates all return fields. Parameters are well-covered. Combined with sibling context, the tool is fully understandable.
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 coverage is 100%. The description adds value by explaining the format options and specifying IANA timezone names, but the schema already defines them with defaults. Baseline 3 is appropriate.
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 gets current time in any timezone and lists specific returned fields. It is distinct from siblings get_astronomy and get_moon_phases which are in different domains.
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 does not explicitly state when to use this tool vs alternatives, but the sibling tools are astronomy-related, making context clear. No exclusions or alternative guidance provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Get upcoming moon phases (New Moon, First Quarter, Full Moon, Last Quarter) and current moon illumination percentage from the US Naval Observatory.
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | Start date in YYYY-MM-DD format (default: today) | |
| count | No | Number of phases to return (default: 4, max: 99) |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden of disclosure. It describes the tool as a read-like operation ('Get'), but does not explicitly state it is non-destructive or mention potential side effects. The absence of explicit behavioral traits beyond the obvious limits transparency.
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?
The description is a single 24-word sentence that is front-loaded with the primary action and key output details. Every word contributes meaning; no redundancy or fluff.
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?
Given the absence of an output schema, the description adequately explains the return value (upcoming phases and current illumination). However, it could be more explicit about ordering (chronological) and the precise meaning of 'current illumination' (e.g., for today).
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 coverage is 100% with descriptions for both parameters. The description adds value by explaining the output (list of upcoming phases and current illumination) and the source, providing context beyond the schema definitions.
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 retrieves upcoming moon phases (listing four specific types) and current moon illumination percentage from a specific authoritative source (US Naval Observatory). It distinguishes itself from siblings like get_astronomy (broader) and get_current_time (time-only).
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 implies usage for moon phase data but does not provide explicit guidance on when to use this tool over alternatives like get_astronomy. No when-not or exclusion criteria are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
get_astronomyget_current_timeget_moon_phases
