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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful behavioral context: it is a legacy implementation of `search` and that the return format differs from `search`. It does not specify the exact old return shape, but the deprecation context and format difference are meaningful disclosures beyond the annotations.

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?

Two compact Japanese sentences with no wasted words. The legacy status is front-loaded, the functional similarity to `search` is stated, and the recommendation to use `search` comes last as a natural conclusion.

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 low-complexity legacy tool, the description covers selection well: it identifies itself as an alias, distinguishes the return format, and routes new callers to the preferred sibling. However, since there is no output schema and the return format is the tool's distinguishing trait, the description stops short of explaining what that old format actually looks like.

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?

The description adds no parameter-level meaning. Schema coverage is only 50%, and the description does not clarify what `limit` controls or how it interacts with results. The `query` parameter is documented in the schema with an example, but the description itself contributes nothing to parameter understanding.

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 states a clear verb and resource: it searches within the site (サイトの中を探します), just like `search`. It also differentiates itself from the sibling `search` by noting the return format is different, and marks itself as a legacy alias for previously connected users.

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 explicitly says this tool is kept for people already connected and instructs new usage to go to `search` instead: '新しく使うときは search を使ってください'. This is unambiguous when-to-use versus when-not-to-use guidance with a named alternative.

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