エリア別の在庫

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds that it returns counts and feature pages, and the phrase '主要エリア' hints at a possible scope limitation. However, it does not disclose return format, pagination, or data freshness; with no output schema, this is a moderate gap.

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?

A single sentence that front-loads the return content and closes with the intended use case. No filler or redundant restatement of the title.

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?

This is a parameterless read-only list operation with strong annotations. The description fully specifies what it returns and when to use it; no invocation complexity is missing. An agent can confidently call and interpret this tool without further documentation.

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 schema has zero parameters and 100% schema description coverage, so there is nothing for the description to compensate for. Baseline for 0 params is 4; no additional parameter detail is needed.

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 specific verb (返します) and a concrete resource: prefecture-level facility counts, major areas, and editorial area feature page list. It also frames the tool as a pre-search rough targeting aid, which distinguishes it from search siblings. This is above the minimum viable and leaves no ambiguity about what the tool does.

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 to use it before searching for rough targeting (検索前の当たり付けに使います), providing clear context for when to invoke it. It does not explicitly name sibling tools or give exclusions, so it stops just short of a 5.

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