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

Annotations already signal read-only and open-world behavior, and the description adds important operational context: pagination is supported and next_page_token must be passed back unchanged. It informs agents of a common failure mode (truncating/masking tokens) and reinforces token reuse constraints, which goes beyond the annotation fields.

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 compact and front-loaded: purpose first, then usage boundaries, then pagination instructions. Every sentence adds useful guidance and there is no filler or vague language.

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 read-only search tool with only two parameters, an output schema, and high schema description coverage, the description fully covers when to use the tool, which alternatives to choose, and how to handle pagination. Nothing needed for correct invocation is missing.

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?

The input schema already covers both parameters with descriptions, so baseline is 3. The description repeats the page_token handling rules but does not add materially new parameter-level meaning beyond what the schema already documents.

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 clearly states the tool searches Xiaohongshu products by keyword, using the verb '搜索' with the specific resource '小红书商品'. It also distinguishes itself from product detail and review tools by explicitly saying those should be used when a full sku_id is already available.

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?

It explicitly states when to use this tool (search-term-based product lookup) and when not to use it (when a complete sku_id exists, use product detail or review tools instead). It also gives precise instructions about page_token continuation, leaving no ambiguity about pagination behavior.

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