Moon & Star Map

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

The annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds useful context by saying results are computed with astronomical algorithms and by enumerating the returned values and capability limits, though it does not discuss calculation accuracy or timezone edge cases operationally.

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 front-loaded with "Use this when" and then proceeds through return contents and exclusions in a compact, scannable structure. Every sentence contributes either usage context, capability boundaries, or output expectations.

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?

With an output schema and informative annotations already covering much of the contract, the description supplies the remaining intent, exclusions, return summary, and usage contexts needed for correct invocation. No major ambiguity remains for an agent deciding whether and how to call it.

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%, so city, dates, month, and labels are already fully documented in the input schema, which sets the baseline at 3. The description reinforces likely usage through birthday, couple, and monthly-calendar examples, but it does not add syntax or constraints beyond what the schema provides.

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 states a specific resource and outcome, including returned fields such as phase name, illumination, moon age, and exact phase times. It excludes adjacent domains like astrology, tides, moonrise, planets, and eclipses, but it never names or directly contrasts the sibling tools generate_moon_poster and generate_star_map, so sibling differentiation is only implicit.

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?

It explicitly lists when to use the tool: birthday/wedding/first-date moons, today or tonight, couple comparisons, and monthly calendars. It also lists clear exclusions, but it does not explicitly route related requests such as a moon poster to the sibling generate_moon_poster.

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

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

Annotations already declare read-only, idempotent, non-destructive behavior, so the bar is lower. The description adds useful context about computed real phases, returned preview plus vector PDFs/SVG, and that prints are not sold or shipped, though it does not mention auth, limits, or other operational constraints.

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?

Front-loads the use case, then covers modes, outputs, and the exclusion in a compact, well-structured way. Every sentence carries useful selection or behavioral information.

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 existing output schema, annotations, and fully described parameters, the description provides enough context to choose the tool and understand its main modes and output artifacts. No critical gap remains.

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 description coverage is 100%, so the schema already documents all parameters and enums. The description echoes the three poster kinds but adds no syntax, constraints, or parameter details beyond what the schema provides.

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?

States a specific verb and resource (generate moon poster) and distinguishes the three supported poster kinds: single moon, pair, and yearly lunar calendar. It also names the sibling tool it is not, making selection unambiguous.

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?

Explicitly gives when to use it (printable poster, special date, couple print, yearly calendar) and when not to use it (quick phase answer should use find_moon_phase). The alternative is named directly.

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

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

The annotations already establish that this is a safe, read-only, idempotent, non-destructive operation. The description adds substantial behavioral context beyond annotations: it computes real star positions, handles local time including time zones and DST, returns a preview and multiple vector poster formats, and explicitly notes that it takes a city rather than coordinates.

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 front-loaded with the primary use case and remains dense with useful detail. Each sentence contributes either usage guidance, behavioral capability, input constraint, or scope limitation, and there is no wasted filler.

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 tool's complexity, full schema coverage, annotations, and an output schema, the description is complete enough for correct invocation. It covers the main purpose, input constraint, behavioral scope, output formats, and exclusions without needing to explain return values in detail.

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 description coverage is 100%, so the schema already documents all nine parameters with examples, defaults, and constraints. The description reinforces that the city must be a name rather than coordinates and that local time is handled, but it does not add much parameter-level meaning beyond the schema.

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 states a specific verb and resource: generating a star map or night sky poster for a date and place, with concrete examples. It is clear, but it does not explicitly differentiate itself from the sibling generate_moon_poster tool, so it falls short of the top score despite strong specificity.

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?

It gives clear when-to-use conditions (birthday, wedding, anniversary, the night they met, or tonight) and when-not-to-use cases (not planets, not navigation, not telescope pointing). It does not name alternatives among the sibling tools, so it stops short of a 5.

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