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

Annotations already declare readOnlyHint=true, so the description does not need to repeat safety. It adds value by specifying 'public' and 'top-level' comments, but it does not disclose behavior such as pagination limits, rate limits, or how many comments are returned. This is acceptable but not strong.

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 front-loaded sentence with no filler or repetition. It communicates the core operation efficiently; the schema carries the detailed parameter behavior.

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?

The schema is rich and an output schema exists, so the main gaps are not about return values. However, the description does not explicitly route the agent to youtube_get_video_comment_replies for replies or provide any usage context beyond the basic operation. It is minimally complete but lacks helpful cross-tool guidance.

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 the schema already provides detailed explanations for video_url, sort_type, and page_token. The description adds no parameter-level meaning beyond the schema, so the baseline of 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?

The description states a clear verb and resource: 'get public video top-level comments based on a YouTube video link.' The phrase '一级评论' (top-level comments) distinguishes it from the sibling tool youtube_get_video_comment_replies, so an agent can tell them apart.

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 implies usage for top-level comments only by saying '一级评论', but it does not explicitly state when to use this tool versus youtube_get_video_comment_replies or mention conditions for choosing alternatives. There is no exclusions or when-not-to-use guidance.

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