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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description adds useful domain context (UTC/Beijing time output; role in BaZi and leap months). It does not add operational details such as whether all 24 terms are always returned, count limits, or how language affects output. No contradiction.

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 tight sentences, front-loaded with the main resource and then the domain role; the group/cost tags are metadata and don't bloat the prose. No 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?

For a low-complexity lookup with an output schema, the description establishes what the tool returns and why it matters. It leaves open the when-to-use decision and two undocumented input parameters, so an agent still has gaps before invoking it confidently.

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 50%: fields and precision have descriptions, while year and language do not. The description adds no parameter-level meaning, such as whether fields supports solar-term paths, what language controls, or why year is bounded 2–2899. It fails to compensate for the coverage gap.

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 exactly what is returned: the 24 solar terms for a given Chinese solar year as exact instants in UTC and Beijing time. It even explains the 12/12 split between BaZi pillar months and leap-month determination, so the resource and its significance are clear. It does not explicitly differentiate itself from nearby Chinese-calendar siblings, so 4 rather than 5.

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?

Explains what the data is for (BaZi month boundaries and leap-month placement) but never states when to call this instead of alternatives like astroway_bazi_month_pillar, astroway_chinese_lunar_date, or astroway_chinese_tong_shu. Usage is implied by domain context, not directed.

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