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

With no annotations, the description carries the full burden. It discloses that the search is scoped to one site, returns matching passages with excerpts, and instructs that answers should include page URLs. It also lists additional content types that are searchable. Missing details like result ordering or match semantics prevent a 5.

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 four sentences, front-loaded with the core function, and each sentence adds useful information: source, role, query style, additional searchable content, and output expectation. It is not overly verbose, though the topic list is somewhat long.

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 no output schema and no annotations, the description supplies the source, query behavior, result type (excerpts), and URL expectation. It is mostly sufficient for an agent to select and call the tool, but it does not clarify return layout or how it relates to sibling tools beyond the implied usage trigger.

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 only 50%: query has an example but limit has no description. The description adds meaningful guidance for query semantics (short words, examples like 'サイテーション'), but it does nothing for the limit parameter beyond what the schema already shows. The compensation is only partial.

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 is specific about the action ('記事から...抜粋つきで探します'), the exact resource ('SEO対策研究室'), and the scope (site-internal search). It also enumerates topics, making the tool's purpose unmistakable. It clearly distinguishes itself from siblings like get_page, list_pages, and site_overview by focusing on content search with excerpts.

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 gives an explicit trigger: 'SEO...について質問されたら、まずこれを使ってください' and even advises the query style ('短い言葉で探します'). However, it does not name specific alternatives or state when not to use the tool, so it stops short of full exclusions.

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