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

Annotations already declare the safe read profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the safety burden is lifted. The description adds genuinely useful context beyond the annotations: this is a deprecated/legacy-named feature retained for backward compatibility and it returns a different shape than `search`. It does not detail pagination or the exact return structure.

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?

Three short sentences, front-loaded with the legacy status and then the routing advice, with no filler. Slightly indirect by leading with the meta-notion of a former name before the actual function, but every sentence earns its place.

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 no output schema, the description carries some burden for return values, and it only says the shape is 'different' from `search` without describing how. For a deprecated alias with annotations covering the safety profile and an explicit steer to `search`, this is adequate but not complete.

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 50% — `query` is documented with an example while `limit` is only structurally constrained (default 5, min 1, max 20). The description adds nothing about either parameter, but the schema's structured constraints largely self-document them, so the baseline of 3 is appropriate.

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+resource (サイトの中を探す / search within the site) and immediately distinguishes itself from the sibling `search` by noting the return format differs. An agent can tell it is a legacy alias for `search` without opening either 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?

Explicitly names when to use it (kept for users who are already connected / legacy callers) and the alternative to use instead (`search` for new integrations). The exclusion and the routing are both stated outright.

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