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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds no further behavioral context: nothing about suggestion result shape, language handling, or rate limits beyond the one-line scope statement, and the scope statement largely duplicates the purpose.

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 front-loaded sentence stating what it does, followed by a semicolon-delimited exclusion. Zero filler, and the most important information leads.

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 one-parameter read-only lookup with an output schema and full schema coverage, the description is sufficient to call the tool correctly. The only real gap is that it never points to the sibling search tools that should be used for the excluded cases.

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% and the single parameter's schema text already excludes links, user IDs, and page_token, so the description cannot add much. It confirms the keyword drives the suggestion lookup but contributes no format or length guidance beyond the schema.

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 names a specific verb and resource: retrieving Bilibili search-box autocomplete suggestions from a keyword. It also adds a negative scope clause ("不用于搜索用户或内容") that separates it from the sibling search_users/search_videos/search_articles family, though it does not name those siblings explicitly.

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 states when not to use the tool — for searching users or content — which is exactly the confusion an agent would have given many similarly named search siblings. It stops short of naming the correct alternative tools (e.g., bilibili_search_videos) to route to instead.

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