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 fully covered. The description adds a genuinely non-structured behavioral trait — the 10-credit Tier 1 cost — which is useful for a cost-aware agent, but says nothing about return shape, limits, or auth.

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?

One tightly written line front-loads the substantive output description, with group and cost tags after it. Nothing is wasted, though the tags are boilerplate rather than value-adding prose.

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?

For an 8-parameter tool with four undocumented parameters, the description is thin. An output schema and annotations exist so return values and safety need not be restated, but the ambiguity between date and solarYear is left entirely unresolved.

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 only 50%, leaving date, time, language and solarYear undocumented. The description mentions 'given solar year' but does not clarify the crucial distinction between the required 'date' and the optional 'solarYear', nor how time/timezone interact with them.

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 names the exact outputs (fixed-branch element, cycling-stem element, yin/yang) and the input dimension (solar year), so the agent knows what this computes. It is distinguishable from siblings like chinese_zodiac_animal, though it never explicitly contrasts with them.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives such as chinese_zodiac_animal or chinese_feng_shui_bagua. The '[Group: Chinese: Zodiac & Feng Shui]' tag implies a domain but does not tell the agent when to select this tool over its siblings.

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