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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds that the return format differs from fetch but does not explain how, which is a minor gap. It does not contradict annotations, and the legacy context is helpful but not rich.

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 two sentences with no wasted words. The legacy context is front-loaded, and the directive to use fetch is placed clearly. It is efficient and easy to scan.

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?

The tool is simple with one parameter, annotations cover safety, and no output schema exists. However, the description does not specify the actual return format, which could be necessary for someone using this legacy tool. Since the description directs new users away, it is adequate but leaves a gap for existing users who need to know the format.

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%, with the url parameter described as 'ページの URL かパス（日本語のままでも可）' (page URL or path, Japanese allowed as-is). The description adds no additional parameter information, so it does not compensate beyond what the schema already provides. Baseline 3 is appropriate given full coverage.

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 clearly states that the tool returns the page body, similar to fetch, but with a different return format. It also identifies itself as a legacy version of a previously named function, distinguishing it from the fetch sibling. However, it does not specify exactly what the return format is, so the purpose is clear but not fully detailed.

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 directs new users to use fetch instead, stating '新しく使うときは fetch を使ってください' (use fetch when using anew). It also notes that this tool is kept for existing users, providing clear context on when to use this tool vs the alternative. This is explicit and leaves no ambiguity.

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