validate_corporate_number

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

With no annotations, the description carries the full burden of disclosure. It adds key behavioral traits: offline operation and that it does NOT confirm registry existence. This is useful context beyond a basic 'validates a number' statement, though it doesn't detail edge-case behavior (e.g., response format or error handling), which is partially covered by the output 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?

Two sentences, no fluff. Front-loaded with action and target, then a crucial limitation. Every word earns its place.

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 validation tool with an output schema present, the description covers purpose, usage, limitations, and parameter meaning. It also differentiates clearly from sibling tools. No obvious gaps for an agent to select and invoke it 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?

The schema provides only a type (string) with zero description coverage. The tool description compensates by specifying the parameter must be a 13-digit Japanese corporate number, giving both semantics and a length constraint. This goes beyond the schema's minimal information.

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 tool's purpose: validate a 13-digit Japanese corporate number using format and check-digit rules. It explicitly distinguishes from sibling tool lookup_corporate_number, which confirms registry existence.

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 when to use this tool (offline validation) and when not to (not for confirming existence), directing users to use lookup_corporate_number for that purpose. This is clear usage guidance with an explicit alternative.

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