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

The description states the tool reads product details, consistent with the readOnlyHint annotation. However, it does not add additional behavioral context such as side effects, rate limits, or error conditions beyond what the annotation already implies.

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 concise and well-structured, with a single clear sentence conveying the purpose and usage condition. The parameter description adds essential detail without redundancy.

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?

The tool is simple with a single parameter, and the description fully covers its purpose and input constraints. Given the presence of an output schema, no further explanation of return values is necessary.

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 parameter description is highly informative, detailing the accepted URL types (short link, product page link, or shared copy containing the link) and explicitly excluding product_id, sku_id, and search terms. This goes far beyond the basic schema.

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 reads product details based on a Douyin product link or shared copy. It also distinguishes itself from other tools by specifying this entry is for link-type inputs only, which clearly differentiates it from the product_id variant.

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 and parameter description provide explicit when-to-use guidance: use this tool only when the input is a link, and avoid passing product_id, sku_id, or search terms. This clearly routes the agent to the correct tool among siblings.

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