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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description's '获取' is consistent with a read-only operation with no annotation contradiction. The description adds a scope constraint (suggestions only, not full search), which is useful. However, it adds no context about result limits, pagination, or failure modes; the presence of an output schema lowers that burden but does not eliminate it.

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 compact sentence with the action and purpose front-loaded, followed by a short exclusion clause. Every element earns its place — purpose, trigger, and scope boundary — with zero filler or redundant wording.

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 tool with 100% schema coverage, a present output schema, and safety annotations, the description covers purpose, trigger, and exclusions adequately. The only modest gap is not naming the exact alternative tools for the excluded cases, which is minor given the low complexity and the descriptive sibling names.

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%, and the schema itself already provides strong parameter guidance — keyword is described as '搜索关键词或短语' plus explicit prohibitions on links, user IDs, and page_token. The description's '根据关键词' merely restates the parameter name without adding meaning beyond the schema. With the schema doing the heavy lifting, the baseline of 3 applies.

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 uses a specific verb and resource combination (获取/获取知乎搜索输入框联想词 — get Zhihu input-box suggestion words), which unambiguously states what the tool does. The exclusion clause '不用于搜索用户或内容' explicitly differentiates it from the sibling tools zhihu_search_content and zhihu_search_users. An agent can identify the tool's function and its boundaries without opening the 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?

The description states the trigger condition — wanting keyword-based suggestion words — and explicitly rules out user/content search via '不用于搜索用户或内容'. This gives clear when-not guidance and implicitly points toward the search_content and search_users siblings, but it stops short of naming those alternatives by tool name, so the routing is not fully explicit.

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