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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds genuinely new behavioral information beyond them: the result includes 调休 arrangements, not just festival days, which prevents the agent from assuming weekends around holidays are always free. It still doesn't say what happens for dates outside the supported year range or the shape of the return value.

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 purpose clause followed by the fields returned, then a compact example. Nothing is padding, though the inline example duplicates the schema's examples field and is therefore slightly redundant.

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 zero-required-param, read-only lookup with no output schema, the description supplies the key missing piece by stating conceptually what comes back (holiday status and festival name). The main remaining gap is scope — which years or regions are covered and what an unknown date returns.

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 already documents the YYYY-MM-DD format and the empty-string default meaning today. The description only repeats the format through an example that is also present in the schema's examples array, adding no syntax or edge-case detail beyond it. Baseline 3 is appropriate.

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?

Names a specific verb and resource: querying China's statutory holidays plus 调休 (make-up workday) arrangements, and enumerates the two answers it gives — whether a day is off and the festival name. That resource is unique among the siblings (time_now, world_time, weather_query all concern different data), so confusion is unlikely, though the description never states the distinction explicitly.

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 by "某天是否放假" — an agent can infer this is the tool to reach for when checking whether a date is a Chinese holiday. There is no explicit when-to-use/when-not rule and no mention of the closest alternatives such as time_now or world_time, which would matter for date-related questions.

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