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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds meaningful behavior beyond annotations: only first-level comments (not replies), default Toutiao ordering, pagination support, and that results can continue from search. It does not discuss auth or rate limits, but for a read tool with annotation coverage this is solid.

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 core purpose is front-loaded in a single sentence, and each clause adds a necessary constraint: ordering, pagination, reply exclusion, and the URL alternative. There is no wasted text.

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?

Because an output schema exists, the description need not explain return values. For a two-parameter read tool, it covers scope, exclusions, ordering, pagination, and the URL sibling, while annotations and schema fill in safety and parameter details. Nothing critical 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 description coverage is 100%, so both post_id and page_token are fully documented in the input schema. The description restates that post_id is a numeric content ID and that pagination is supported, adding the context of continuing search results, but it does not add syntax or format details beyond the schema's own parameter descriptions. Baseline 3 is appropriate.

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 (读取), resource (一级评论), and scope (头条文章、视频或微头条), and explicitly excludes comment replies. It also distinguishes itself from the sibling by routing link cases to toutiao_get_post_comments_by_url. An agent can identify exactly what this returns without opening the 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?

Names the alternative explicitly: 有链接时使用 toutiao_get_post_comments_by_url. It also says the input is a numeric content ID from search results and that replies are not included, which implies the reply-specific sibling for that case. This gives clear when-to-use and when-to-use-other guidance.

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