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

Annotations already declare readOnlyHint=true, and the description adds valuable context beyond that: the dependency on both post_id and comment_id from the same first-level comment, the requirement to pass page_token unchanged and not reuse it across different posts/comments, and the fallback conditional flow. No contradiction with annotations; the description enriches the behavioral profile.

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 front-loads the main purpose and then covers usage conditions and pagination. It is appropriately sized for the complexity, though it could be broken into clearer sentences. Still, it is efficient and well-structured.

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 complexity (two required IDs, pagination, fallback scenarios) and the existence of an output schema, the description covers essential decisions and pagination rules. It does not describe return format (handled by output schema) but sufficiently guides an agent on how to obtain and validate inputs.

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?

Input schema coverage is 100% with detailed parameter descriptions. The tool description itself does not add much beyond the schema regarding parameter format or constraints, though it does reinforce the usage conditions (e.g., when to directly use provided IDs vs. fetching them). This meets the baseline given full schema 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 clearly states the tool retrieves Weibo comment replies for a specific first-level comment, using post_id and comment_id. It explicitly names the resource (comment replies) and distinguishes from sibling tools like weibo_get_post_comments_by_post_id by specifying it is for replies to a first-level comment.

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 provides explicit decision logic: if the user has complete IDs, use them directly; if partial info is available, call the corresponding first-level comment tool to retrieve IDs; if no post location info, ask the user. This clearly guides when to invoke this tool versus alternatives.

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