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

No annotations are provided, so the description carries the full burden, and it discloses nothing: no auth requirements (despite the schema exposing a _token fallback), no rate limits, no read/write nature, no return shape. Four characters cannot cover a behavior profile.

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 bare four-character fragment with no structure or front-loading of actionable information. It is not concise-but-complete; it is simply under-specified.

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 no annotations, no output schema, and a two-parameter input including an auth token, the description should explain what details are returned and how authentication works. It supplies none of this, leaving the agent unable to call the tool confidently.

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%, with bv_id documented as 'BV号' and _token explained as a fallback auth token, so the schema does the heavy lifting and baseline 3 applies. The description adds no meaning beyond the 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 phrase 'B站视频详情' identifies the resource (a Bilibili video) and implies a retrieval/detail operation, which is enough to distinguish it from siblings like bili-adjacent or other-platform video tools. However, it names no explicit verb and gives no scope (which fields, single vs. batch), so the purpose is only implied rather than stated.

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 guidance on when to use this tool versus alternatives such as channels_video, yt_video, or douyin_video. No prerequisites, no mention of required BV id usage context. The agent must infer everything from the name.

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