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

Annotations already cover read-only and open-world safety. The description adds meaningful behavior: it returns only first-level comments, uses Toutiao default order, supports pagination, and excludes comment replies. It does not discuss auth, rate limits, or output shape, but the output schema likely covers the latter.

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?

One compact sentence front-loads the core purpose, then adds exclusions and the alternative tool. No filler or repetition; every clause earns its place.

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 a simple read/pagination tool with rich schema coverage, annotations, and an output schema, the description supplies the remaining decision-critical context: what is returned, what is excluded, and which sibling to use when only an ID is available.

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 url and page_token are already well documented in the schema. The description reinforces URL usage and the ID-only alternative, but does not add syntax or format details beyond what the schema provides; 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 and resource: reads first-level comments through a Toutiao content URL or share text, in default order, with pagination, excluding replies. It also distinguishes itself from the sibling tool for ID-only cases.

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?

Explicitly tells the agent when to use this tool (URL or share text is available) and when to use the alternative (only content ID available, use toutiao_get_post_comments_by_post_id). It also clarifies that replies are excluded, which routes the agent to the replies tool when needed.

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