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

With no annotations provided, the description carries the full burden. It discloses that the calculation is based on 令和8年度 rates, that it is a calculation rather than an estimate, and that results may differ from actual payslips due to 健保組合 or various deductions. It also notes the screen path '/tedori/'. This is meaningful behavioral context beyond the schema.

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 compact and front-loaded: it opens with the core purpose and year, then lists deductions and outputs, then gives trigger phrases, then caveats. Every sentence adds information. It is slightly dense with parentheticals, but nothing is redundant with the schema.

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 calculation tool with 7 parameters and no output schema, the description covers the main inputs, the calculation basis, the output contents, and the key caveat about divergence from actual payslips. It does not explain what happens with invalid or missing optional parameters, but the schema already marks only gekkyu as required. The description is sufficient for an agent to select and invoke the tool correctly.

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%, so the baseline is 3. The description adds context for the main parameter (gekkyu) by explaining how it is used ('月給（額面）を渡すと'), but it does not add detail for optional parameters like age, fuyo, pref, shoyo, tokutei, or haigusha beyond what the schema already provides. The description's mention of 都道府県別 and 扶養 does indirectly clarify pref and fuyo, but not enough to raise the score above baseline.

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 ('計算する') and resource ('手取り'), and enumerates exactly which deductions are included (健康保険・介護保険・厚生年金・雇用保険・所得税・住民税) and what outputs are returned (月/年の手取り、内訳、家賃の目安、ふるさと納税の上限). It also names the consultation phrases that should trigger this tool, which distinguishes it from siblings like furusato or seikatsuhi.

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 gives clear trigger examples ('「手取りはいくら」「住民税はいくら」「額面30万の手取り」の相談にはこれ'), which tells an agent when to use it. It does not explicitly name alternatives or say when not to use it, but the trigger phrases plus the sibling list make the intended usage reasonably clear.

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