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

Annotations already declare readOnly/openWorld=false/no destructive behavior, so the safety profile is covered; the description adds the crucial behavioral boundary that only pre-loaded pages are searched (not the live web, not post-load updates) plus the 'don't fill gaps by guessing' rule. That is real context beyond the structured fields.

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?

Purpose and scope are front-loaded, and despite being a multi-sentence paragraph every sentence adds either routing or behavioral value. It is slightly long, with the rephrase/fallback instructions bordering on over-explanation.

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?

With an output schema present, return-value explanation is not needed, and the description still covers scope boundaries, trigger scenarios, and failure handling. Nothing an agent needs to use it correctly appears to be missing.

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% for the single 'query' parameter, so the baseline is 3. The description earns extra credit by supplying concrete rewriting mappings (e.g., おせち→なごやかセット白鳥, 日焼け止め→白光) that materially improve how the query should be phrased.

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 (search) and resource (excerpts with URLs from the loaded pages of ai-star.co.jp) and names the covered domains/products precisely. It does not, however, differentiate itself from the similar-looking sibling 'search_pages', leaving an agent to infer which site-search tool to pick.

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 says to use this before answering from the model's own knowledge, specifies the topics that trigger it (company products, seasonal items, FAQ, recruitment), and gives a concrete when-not and fallback path: rephrase (with synonym examples), then read candidate pages, and never guess. This is precise routing guidance.

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