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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the non-mutating nature and external-world interactions. The description does not contradict these annotations and adds minor context about how to obtain the IDs, but it does not disclose additional behaviors such as rate limits, error handling, or exactly what happens on invalid IDs. Given annotation coverage, this level is acceptable.

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 description is a single, dense sentence that efficiently conveys the purpose and usage constraints without redundancy. It is front-loaded with the main condition (having the IDs) and then provides actionable routing guidance, maintaining good structure despite being compact.

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?

Given the tool's simplicity (comment list retrieval with pagination), the description adequately covers the primary scenario and input requirements. Output schema handles return values, and page_token pagination is documented in the schema. The description also addresses how to obtain IDs when not supplied, making it reasonably complete for an agent to call correctly.

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 each parameter is already documented. The description adds meaningful value by stating that object_id and object_nonce_id must be passed together and unchanged, and by guiding the agent on where to acquire them if not initially provided. This goes beyond bare schema definitions and clarifies the relationship between the two required parameters.

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 operation — fetching the comment list for a given video — and explicitly names the required identifiers (object_id and object_nonce_id). It clearly differentiates itself from sibling tools like wechat_get_video_comments_by_url (which uses a URL) and wechat_get_video_comment_replies_by_comment_id (which handles replies), so an agent can distinguish it without inspecting schemas.

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?

The description explicitly states when to use the tool (when object_id and object_nonce_id are already available) and provides fallback sources for obtaining them (from detail or first-level comment results). It also tells the agent to call the detail tool first when only an encrypted_object_id is present, effectively excluding the wrong paths and routing to the correct sibling.

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