公开链接预览

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description adds value by specifying that it extracts lightweight data like title, description, site name, canonical, and favicon. No contradictions, and it clarifies the scope of extraction.

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 a single sentence that efficiently conveys the tool's purpose, scope, and use case without unnecessary words. It is front-loaded with key 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 the simple input (one parameter) and the presence of annotations, the description provides adequate context including the output fields and use case. It could be more complete if it described the output format, but the listed fields partially compensate for the lack of an output schema.

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 is fully covered (100%) with a clear description for the single 'url' parameter. The tool description adds no additional parameter meaning beyond the schema, so the baseline score of 3 is appropriate.

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 specifies the verb 'extract' and the resource (公开网页标题、描述、站点名、canonical 和 favicon). It also distinguishes the tool from siblings like cn_webpage_extract by noting it's '轻量' (lightweight) and suitable for group chat link previews.

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 indicates the use case ('适合群聊链接预览'), providing clear context for when to use. However, it does not explicitly state when not to use or mention alternative tools, missing some differentiation guidance.

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