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 structurally. The description adds that results are paginated and that the list is 'complete', but the actual paging mechanics are documented in the schema's page_token, so the added behavioral content is thin. It says nothing about ordering, maximum page size, or what happens with an expired token.

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?

A single sentence, front-loaded with the action and required keys, followed by the sibling routing note. No padding or redundant restatement of the tool name.

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 full schema coverage, explicit annotations, and an output schema, the description only needs to add entry-point routing and pagination awareness — both present. It is slightly thin on the prerequisite chain (you must first call the video-comments tool), which an agent must infer from 'comment_id 取视频评论列表'.

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 all three parameters are already well documented, including the warning not to pass a reply's own ID. The description's note that comment_id comes from the video comment list duplicates the schema rather than extending it. Baseline 3 applies when the schema does the heavy lifting.

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 specific verb (读取) and resource (完整回复列表) plus two identifying keys (video ID, 一级评论 ID), and explicitly distinguishes this entry point from the sibling haokan_get_comment_replies_by_url. An agent can tell it apart from the URL-based sibling without opening either schema.

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?

It routes the agent: comment_id must come from the video comment list, and the URL-based alternative is named for the other entry path. What is missing is an explicit statement of when to prefer this over by_url (i.e., only when you already hold numeric IDs) — the implication is clear but not spelled out.

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