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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. The description usefully adds deprecation status and that the return shape differs from fetch, but it never says how the shape differs, nor anything about errors, limits, or truncation of page bodies.

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 that each carry a distinct load: identity/legacy status, behavior relative to fetch, and migration instruction. The legacy notice is front-loaded. Minor redundancy in naming the site and repeating the backwards-compatibility rationale.

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 single-parameter, read-only legacy alias with no output schema, the description supplies everything needed to decide whether to call it: what it does, that it is superseded, and the preferred alternative. The only omission is the nature of the differing return format, which is low-stakes given the agent is told to use fetch instead.

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% and there is a single 'url' parameter already documented in the schema ('ページの URL かパス（日本語のままでも可）'). The description adds no additional semantics about the parameter, so the baseline 3 applies.

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 and resource ('fetch と同じようにページの本文を返します') and explicitly identifies itself as the former name of the fetch tool, so an agent can place it against its sibling immediately. It is slightly indirect because it defines itself by reference to another tool rather than describing its own output, but the core purpose (read page body) is unmistakable.

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?

Gives both sides of the routing decision: this exists only for already-connected clients ('すでにつないでいる人のために残しています'), and new usage should go to fetch ('新しく使うときは fetch を使ってください'). The alternative is named and the condition selecting it is explicit.

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