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

With no annotations, the description carries the behavioral disclosure burden. It adds useful context by stating the cost per call (¥0.05) and indicating the call is a generation operation that returns title and description, implying no side effects. It does not detail auth or error behavior, but for a simple generation tool this is reasonably transparent.

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 two concise sentences with no filler. It front-loads the purpose, then states input, output, and cost. Every sentence contributes directly to tool selection and invocation.

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 one parameter and the presence of an output schema, the description provides the essential input semantics, output form, and cost information. It could be more explicit about output language or input restrictions, but the platform context and example make the intended usage sufficiently clear.

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 0% and the schema only provides a string parameter q with no description. The description compensates by explaining that q is a product input and gives a concrete example ('九成新Switch'), which conveys the expected format and content. It could add length or formatting constraints, but the guidance is sufficient for a single parameter.

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 a specific function: generating high-conversion Xianyu product copy from a product input and returning a title plus description. It differentiates itself from sibling tools by naming the Xianyu platform and the exact output format.

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 implies usage when a user needs Xianyu product listing copy, aided by the example input. However, it does not explicitly state when not to use it or mention alternatives such as ecom_selling_copy or xhs_viral_note, so routing guidance is only implied.

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