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

Annotations already cover read-only/idempotent/non-destructive safety, so the description earns credit for the extra operational facts: per-call price, billing only on success, automatic refund on failure or empty result, and a hard pagination ceiling imposed by the platform. It does not discuss rate limits, how many comments per page, or ordering, which are the remaining behaviors an agent might care about.

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 sentences, front-loaded with purpose and return fields, then usage, then pricing, then the pagination limitation. Every sentence carries information; nothing is repetitive, though the pricing sentence could have been folded in more tightly.

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 no output schema, the description compensates by listing the returned fields, and it also covers cost and truncation behavior. What is missing is page size and sort order, which an agent would need to reason about paginating fully, so it is complete but not airtight.

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. The description adds real meaning for the `page` parameter by stating that results are paged and that pagination depth is capped by platform visibility, implying further pages return nothing — information the schema does not convey.

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 opens with a specific verb plus resource (获取抖音视频的评论列表) and then enumerates the returned fields (comment text, like count, reply count, commenter nickname/region, timestamp). It is clearly distinguishable from the sibling douyin_product_comments and from other-platform *_post_comments tools.

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 names concrete use cases — sentiment analysis, competitor reputation comparison, public-opinion monitoring — which gives the agent a clear selection context. It stops short of explicitly naming an alternative sibling (e.g. product comments vs video comments) or stating when not to use it, so usage guidance is strong but not exhaustive.

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