Verify a Japanese company

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

Annotations cover the safety profile (readOnly, openWorld, non-destructive), and the description goes well beyond them: the data source (NTA via JP-Verify), that attribution and data_as_of are passed through unchanged, that each call is a metered lookup, and that malformed input is rejected without consuming a call. It also discloses the exact status vocabulary and the meaning of name_en_source values.

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?

It is a dense paragraph but well front-loaded: identifier, then return fields, then the English-rendering caveat, then source and caveats. Every clause carries information, though the single block is longer than strictly necessary for a one-parameter tool.

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 no output schema, the description carries the full burden of describing returns and does so completely: status values, dates, Corporate Number, name/address fields, the name_en_source semantics, and the reduced payload for sole proprietors. An agent has everything needed to call and interpret the result.

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% for the single 'number' parameter, so format and full-width/hyphen tolerance are already documented in the schema. The description's '(T + 13 digits)' adds only a small structural clarification over the schema example, so the baseline 3 is appropriate.

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 (check/verify), resource (a Japanese business), and the two accepted identifier forms, so an agent immediately knows this is a single-entity number lookup. It does not explicitly name or contrast itself with find_japanese_company_by_name or the batch sibling, but the 'by its ... number' framing implicitly separates it from name-based search.

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?

Usage is implied by the identifier-based framing and the note that a malformed/mistyped number is rejected without a call, which tells the agent when this tool will and won't spend a lookup. However, there is no explicit when-to-use-this-vs-the-batch-or-name-search guidance and no stated prerequisites.

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