houjin_corporation

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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the data source (National Tax Agency registry) and the 'one' result constraint, which are useful, but it does not mention behavior for missing numbers or output format.

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 a single 20-word sentence, front-loaded with the verb 'Look up', and every word is meaningful. It is compact and well-structured.

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 simple single-parameter lookup tool with no output schema, the description is adequate: it states the scope, the data source, and the lookup mechanism. It could benefit from noting not-found behavior or return fields, but these are not critical for the basic use case.

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 input schema already describes the 'number' parameter with 100% coverage as 'A 13-digit Japanese corporate number.' The tool description repeats the same format and adds the Japanese term 法人番号, but provides no additional semantic detail beyond the schema.

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 clearly states the action ('Look up'), the specific resource ('one Japanese corporation'), and the exact lookup key ('13-digit corporate number'). This distinguishes it from sibling tools like houjin_search (likely multi-result search) and houjin_verify (verification).

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 usage context is implied: use this when you have a 13-digit corporate number. However, the description does not explicitly name alternatives or state when not to use it, leaving the agent to infer selection relative to sibling tools.

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