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

Annotations already establish read-only, idempotent, closed-world behavior, so the description only needs to add context. It does that usefully by disclosing the data source, dual time zones (UTC and Beijing), and an accuracy bound relative to the Hong Kong Observatory.

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?

A single front-loaded sentence with the resource and range stated first, followed by the time-zone and accuracy qualifiers. No wasted text.

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 no output schema, the description usefully signals what is returned (instants in UTC and Beijing time) and the year bounds. It could say more about the shape of the returned list, but is adequate for a one-parameter lookup.

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% and the single parameter is fully documented, so the schema carries the semantics. The description restates the 1900-2100 range already enforced by the schema's min/max, adding no new syntax or format detail.

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 the specific resource (the 24 solar terms) and scope (a calendar year, 1900-2100), so the agent knows exactly what it retrieves. It does not explicitly distinguish itself from the sibling tools, but the resource is distinctive enough that confusion is unlikely.

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?

Usage is only implied: needing solar-term dates/times for a given year. There is no statement of when to use this over bazi_pillars, best_times, or qimen_chart, nor any prerequisites or exclusions.

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