douyin_comments

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It reveals a login cookie requirement and a limitation of only returning the first screen of comments, which is useful. However, it does not describe error scenarios, data formats, or whether the operation is strictly read-only, leaving gaps in transparency.

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 sentences long and front-loaded with the core purpose. It avoids redundancy and clearly separates the tool's action, the authentication requirement, and the parameter origin, with no unnecessary words.

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 tool with 2 parameters, a full schema, and an output schema, the description covers the essential use case: fetching first-screen comments with a required cookie and tying video_id to search results. It misses minor details like pagination behavior beyond the first screen and error handling, but these are partially covered by the presence of an output schema and the tool's simplicity.

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 schema already provides descriptions for both parameters (limit and video_id), achieving 100% coverage. The description adds critical semantic context by explaining that video_id comes from the 'video_id' field of douyin_search results, which goes beyond the schema's simple '视频 ID' and helps the agent source valid inputs.

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 the tool's action and resource: '获取抖音视频评论' (get Douyin video comments) with a scope qualifier '（首屏）' (first screen). It distinguishes from sibling tools like douyin_search and douyin_video by focusing specifically on comments for a video.

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 provides a usage prerequisite: '需要登录 cookie' (requires login cookie) and indicates that video_id comes from douyin_search results, giving explicit source context. It does not explicitly mention alternative tools for other platforms, but the name and context make the intended use clear.

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