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

With no annotations, the description carries the full burden and does substantial work: it warns that values must be replayed verbatim (no translation, case changes, or dropping the ';' in 'Parent;Leaf'), that labelZh is display-only, and that count should be used to avoid over-narrowing. It does not state read-only/side-effect status or any auth requirement, so it falls just short of complete.

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?

Purpose, usage, args, and returns are front-loaded and clearly sectioned, and every sentence carries content. It is, however, fully duplicated across Chinese and English, which doubles the length for any single reader.

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?

There is no output schema, so the description must explain the return shape, and it does so precisely: per-facet { param, values } with { value, labelZh, count } items, plus a top-level labels[] describing 320 libraries. An agent has everything needed to call and interpret it.

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%, so the baseline is 3, but the description adds real meaning: it clarifies that 'field' matches a facet name substring and that 'query' filters against values and their Chinese labels, with a concrete non-Latin example (query="悲伤") that the schema does not provide.

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 ('列出曲库全部可用的筛选值 / Lists every filterable facet value in the catalog') and enumerates the facet domains covered. It is clearly distinguishable from km_search, which it explicitly references as the consumer of these values.

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 an explicit precondition: 'Call this BEFORE using any include*/exclude* filter in km_search.' It names the sibling tool and the exact condition that should trigger this call, leaving nothing to inference.

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