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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so safety is covered. The description adds genuinely useful behavioral context the annotations cannot carry: per-call pricing (¥0.2), billing only on success, automatic refund on failure or empty results, and the single-page buffer-cursor model. It omits auth requirements (the _token/header alternative) and any rate limits, so it is good but not exhaustive.

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?

Four short sentences, each front-loaded with a distinct payload: what it returns, when to use it, the speed shortcut, then the billing terms. No filler and no repetition of the parameter names.

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?

There is no output schema, yet the description compensates by naming the returned fields (content, likes, IP location, featured flag, reply count and reply list) plus the pagination and billing model. For a 5-parameter read tool with full annotation coverage, nothing an agent needs in order to call it correctly is missing.

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%, so the baseline is 3, but the description adds real meaning beyond the schema: it explains the cursor flow (首页留空，传上一页响应的 buffer) and, more importantly, the performance rationale for comment_id (taken from 文章详情, roughly doubles speed). That tip is not derivable from the parameter description alone.

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?

States a specific verb and resource (获取…一级评论) plus the scope qualifier 一级评论 (top-level only) and 单页 (single page), so an agent immediately knows this is not a full-thread or sub-reply fetcher. It also enumerates the returned fields, making the tool's output distinguishable from sibling comment tools at a glance.

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?

Gives a clear usage context (评论舆情、用户反馈分析) and an actionable prerequisite tip — fetch 文章详情 first to obtain comment_id for a 2x speedup. It stops short of explicit when-not-to-use guidance or naming an alternative tool for nested replies, so it is clear but not complete.

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