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

Annotations already declare readOnlyHint=true and destructiveHint=false, lowering the burden for safety disclosure. The description adds meaningful behavioral specifics beyond that: the exact payload fields returned, the inclusion of solar terms, and the default behavior that omitting year/month returns the current month. This is valuable context beyond what annotations provide, though no additional caveats like pagination are mentioned.

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?

Four sentences, all substantive, with the core operation front-loaded in the first sentence. Every sentence earns its place: what is returned, why it exists, the default behavior, and the intended audience. No filler or repetition.

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?

Despite having no output schema, the description enumerates all the data fields returned, describes the default month-in-progress behavior, and situates the tool for calendar UIs and almanac pages. With only optional parameters and a read-only annotation, nothing essential is missing for an agent to select and call this 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 description coverage is 100%, so the baseline is 3. The description only rephrases the default year/month behavior already documented in the schema ('Omit the year and month to get the month in progress' mirrors the schema's default notes). It provides no additional syntax, format, or combination semantics beyond the schema, so it earns exactly the baseline.

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 opens with a specific verb ('Return') and an exact resource: every day of one Gregorian month with its lunisolar date, three pillars, day officer, lunar mansion, clash animal, and solar terms. This clearly distinguishes it from sibling tools like get_chinese_astrology_calendar_day_date (single day) and get_chinese_astrology_calendar_solar_terms_year (yearly solar terms).

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 gives clear usage context: 'the month view a calendar widget renders in one call rather than thirty one' and 'Built for calendar UIs, almanac pages, and planning tools that show a whole month at a glance.' It implies the alternative (calling the day endpoint 31 times) but does not explicitly name the sibling tool or state when not to use it, so it stops short of full exclusion guidance.

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