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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and scope are covered. The description adds nothing further: no note on what an 'issue' contains, whether the archive is bounded, or any rate/auth constraints, so it contributes almost no behavioral context beyond the annotations.

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?

One sentence, front-loaded with the verb and resource, and zero filler. Nothing redundant or padded.

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?

With an output schema present, return values need not be described, and a single optional parameter is fully documented in the schema. The definition is sufficient to call the tool correctly, with only minor gaps around the nature/bounds of the weekly archive.

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 100% and the single parameter's own description already explains that it is an optional positive issue number and that omission returns the latest issue. The tool description adds no syntax, range, or format detail beyond the schema, so the baseline 3 applies.

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?

States a specific verb and resource: fetching one issue from Bilibili's weekly selected-video archive. It is reasonably distinguishable from siblings like bilibili_popular, bilibili_ranking, and bilibili_must_watch, though it does not explicitly name how it differs from them.

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?

There is no when-to-use guidance, no mention of alternatives among the many bilibili_* siblings, and no prerequisites. The only routing signal comes indirectly from the schema note about omitting the number to get the latest issue.

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