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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral context beyond that: the omitted-date default (today, UTC+8) and the queryable window (365 days back to 7 days forward), which an agent cannot infer from structured fields. It does not describe result volume or pagination, so it falls short of a 5.

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?

Three tight sentences, front-loaded with what the tool returns before the usage triggers and the alternative. No filler, and the redirect to the sibling is placed last where it does not interrupt the primary description.

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 single-optional-param read tool with no output schema, the definition covers purpose, defaults, limits, and the sibling alternative. The only gap is what the returned payload looks like (fields, ordering, size), which the absence of an output schema leaves slightly under-specified.

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 param is fully documented with format and example, so the baseline would be 3. The description adds the default-on-omission behavior and the valid date range, which the schema does not express, giving it real added value.

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 (查询赛程与比分), the coverage (足球、篮球、网球、棒球等全部联赛与杯赛), and the date granularity. It also explicitly contrasts itself with get_live_matches, so an agent can distinguish it from siblings without opening a schema.

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?

Gives concrete trigger phrasings (「今天有什么比赛」「昨天的赛果」「周末的赛程」) and names the alternative with the condition that selects it: use get_live_matches if only currently-playing matches are wanted. Both when-to-use and when-not-to-use are covered.

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