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

Annotations already provide readOnlyHint=true and openWorldHint=true, so the description does not need to restate safety. It adds behavioral detail about pagination: '支持 page_token 翻页' and instructs to use the same note_id/comment_id for pagination. No contradiction with annotations.

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?

Description is a single, dense sentence using semicolons to separate distinct instructions. All statements are relevant: purpose, usage conditions, and pagination. No fluff, but slightly dense; could be broken into bullet points for clarity. Still efficient.

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 output schema present and full parameter documentation, description provides sufficient context: purpose, usage flow, and pagination. It does not discuss error handling or rate limits, but given read-only annotation and existing schema, this is adequate.

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 coverage is 100% with detailed descriptions for note_id and comment_id (e.g., '不得截断、缩写、脱敏' etc.). The description adds contextual usage guidance (when to use directly vs. when to call other tools) but does not significantly augment parameter meaning beyond schema. Baseline 3 given high coverage.

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 explicitly states the tool's function: '根据 note_id 和一级评论 comment_id 获取二级评论' (get sub-comments based on note_id and first-level comment_id). It clearly distinguishes from siblings by mentioning '一级评论' and '二级评论', separating it from tools like xhs_get_note_comments_by_note_id which fetch first-level comments.

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?

Provides explicit when-to-use instructions: '用户已提供完整合法的 ID 组合时直接使用' (use directly when complete IDs provided), and when to call alternative tools: '已有 note_id 或笔记链接但缺少必需 ID 时，调用对应一级评论工具补全' (call corresponding first-level comment tool when missing required ID), and when to ask user: '缺少笔记定位信息时向用户索取'. This clearly routes the agent.

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