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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value by warning that results differ under two conventions (Lunar New Year vs. 立春/BaZi), which affects interpretation of the output. It does not cover return structure beyond a list of fields or explain what the optional time/city inputs alter.

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-loaded with the primary output and the differentiating boundary rule, then example queries. Compact overall, though the example-phrase list is slightly padded for the value it delivers.

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, and the description does list what is returned (animal, element, yin/yang, lunar birthday), which is the right compensation. But for a tool with four params and a non-trivial boundary calculation, it omits how optional birth time/city/timezone affect correctness, leaving a real gap for an agent deciding which inputs to supply.

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%, with each parameter (birth_city, birth_date, birth_time, birth_timezone) documented in the schema itself. The description adds no parameter-level guidance and never mentions why city/time/timezone matter for a zodiac computation, so it does not exceed the schema 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?

States a specific verb and resource (Chinese zodiac animal, element, yin/yang for a birth date) plus an additional output (lunar birthday). The boundary-rule detail (Lunar New Year vs. Start of Spring/立春) makes it distinguishable from sibling tools like get_four_pillars and convert_lunar_date without opening their schemas.

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?

Provides concrete trigger questions in both English and Chinese ('what is my Chinese zodiac', 'what animal is someone born in January 1990', '我属什么'), which maps well to user phrasing. However, it names no alternatives or exclusions, so an agent must infer when to prefer get_four_pillars or convert_lunar_date instead.

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