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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful behavioral boundaries beyond them: no video/user payloads and no pagination support, which tells the agent not to attempt paging. It does not need to describe returns since an output schema exists.

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 tight sentence with three clauses, front-loaded with verb and resource, then scope limits. Every clause carries distinct information (purpose, use case, exclusions) and there is no filler.

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?

For a single-parameter, read-only suggestion endpoint with an output schema, the description supplies everything an agent needs: purpose, intended use, and the two boundaries (no content results, no pagination) that most affect invocation.

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?

There is a single parameter with 100% schema description coverage, so the schema already explains 'keyword' and even warns against links/pagination tokens. The description adds no parameter-level detail beyond what the structured data provides, which is the expected baseline.

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 ('获取好看视频搜索联想词') and immediately delimits scope with what it does not return (videos or users), which cleanly separates it from siblings haokan_search_videos and haokan_search_users. An agent can pick this tool without opening any 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?

Gives a clear use case ('用于补全或扩展关键词') and implicitly routes away from content-search tools by stating it returns no video/user results. It stops short of naming the alternative tools or the condition for preferring this one over them, so it is clear but not fully explicit.

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