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

The description adds important behavioral detail beyond the readOnlyHint annotation, especially around pagination: the returned next_page_token must be passed verbatim as the next page_token, and pages cannot be truncated, abbreviated, masked, or replaced with ellipses. This is a concrete, actionable constraint that affects correct invocation.

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?

The description is appropriately brief and well-ordered: it states the core operation first, then explains how to obtain the ID, then the support parameters and pagination behavior, and finally which inputs are not supported. Every sentence adds useful operational information.

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?

Given that an output schema exists and the annotations already signal read-only and open-world behavior, the description covers all essential invocation details: how to get the required id, how to paginate correctly, and what not to pass. No critical usage gap remains.

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 description coverage is 100%, so the input schema already documents all parameters. The description largely reinforces the same information, such as sku_id provenance and page_token integrity, without adding significant new meaning beyond what the schema provides.

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?

The description explicitly states the tool's function — 根据小红书商品 sku_id 获取商品评价 — giving a specific verb, resource, and identifier type. It also differentiates from other tools by stating what it does not support: 商品链接、spu_id 和搜索词, and it points to xhs_search_products as the source for missing sku_id 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?

The description provides a clear usage rule: 已有该 ID 时直接使用，否则可从 xhs_search_products 获取. This tells the agent when to use this tool directly and when to first call another tool. It also gives a strong when-not cursor by rejecting product links, spu_id, and search terms as inputs.

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