rank_listFetch Bilibili video rankings by partition and type, including titles, links, uploaders, stats, and tags. Control result count and tag completion for targeted data retrieval.
获取 B 站排行榜（对应 /v/popular/rank/all）。返回标题、BV 号、链接、UP 主、分区、统计与标签。标签需逐条补齐，默认只补前 20 条。
| Name | Required | Description | Default |
|---|---|---|---|
| rid | No | 分区 ID；0 为全站 | |
| type | No | 榜单类型 | all |
| limit | No | 返回条数 1-100 | |
| tag_limit | No | 最多为多少条视频补齐标签 | |
| include_tags | No | 是否补齐标签（默认 true） |
Changes observed during successful MCP inspections.
v0.1.0-beta.2Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds useful behavioral context: it lists the returned fields and discloses that tags are completed item by item with only the first 20 filled by default, which signals extra latency/work when tag_limit or include_tags are changed.
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?
Three compact sentences: purpose plus endpoint, return fields, then the tag-completion caveat. Every sentence carries information, and the operationally important caveat is front-loaded enough to be noticed.
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 five-parameter read tool with no output schema, the description supplies the return field list and warns about per-item tag fetching, which is sufficient to invoke it correctly. It stops short of explaining the meaning of the type enum or rid values, and does not relate this endpoint to the other ranking tools.
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 description coverage is 100%, so 3 is the baseline. The description adds real meaning to tag_limit/include_tags by explaining that tag completion is done per item and defaults to the first 20, clarifying the cost implication of raising those parameters beyond what the schema states.
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 ('获取 B 站排行榜') and even gives the backing endpoint (/v/popular/rank/all). However, it does not distinguish this tool from the overlapping sibling list tools such as popular_list, weekly_list, and precious_list, so an agent must infer the difference.
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?
No when-to-use, when-not-to-use, or alternative guidance is given. With four similar ranking/list siblings in the tool set, the absence of routing guidance leaves the agent to guess which endpoint to call.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.