Format a Japanese bank-transfer account name (振込名義カナ)

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds real context beyond that: it discloses the return shape (ok, zengin, display, length, entities, changes, errors, warnings), the meaning of 'length' as a voiced-kana count, and that warnings/errors carry English and Japanese messages. It does not cover truncation behavior against max_length, which is slightly relevant for a mutation-free but warning-emitting tool.

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 purpose is front-loaded in the opening clause and every sentence carries transformation or I/O detail. It is a long run-on paragraph with example-level rules (ッ->ﾂ) that are dense but still earn their place as expectation-setting; a bulleted structure would have improved scanability.

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 only two parameters and no output schema, the description carries the return-value burden itself and does so by listing every response field plus the entity/change/warning vocabulary. Nothing an agent needs in order to call it correctly or interpret the result is missing.

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 coverage is 100%, so the baseline is 3; the description earns above baseline by specifying exactly which input scripts are accepted (hiragana/katakana in full or half width, Latin, digits) and that kanji legal-entity words must be spelled out. max_length is left entirely to the schema, which is acceptable 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 states a specific verb and resource ('Turn a payee or payer name into the form Japanese banks accept in transfers (Zengin)') and enumerates the exact transformations. It never names the siblings zengin_name_match or zengin_name_check, so an agent must infer that this is the conversion tool rather than the comparison or validation one.

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?

It gives one important usage constraint ('It does NOT read other kanji: pass the reading'), which tells the caller what input it cannot handle. However, there is no explicit guidance on when to choose this over zengin_name_match or zengin_name_check, so tool selection is only implied by the verb 'format'.

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