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

No annotations are provided, so the description must carry the full burden. It discloses the authentication requirement and self-serve nature, but lacks details on side effects, response format, or idempotency. For a creation tool, this is adequate but not comprehensive.

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 two sentences (English and Japanese), front-loaded with the purpose and key requirements. Every sentence provides essential information without redundancy.

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?

Given 9 parameters (1 required, no output schema), the description covers the most critical aspects: authentication, trades, and location. The schema descriptions handle the remaining parameters in detail. The description provides a good overview, though could briefly mention other parameters for completeness.

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 baseline is 3. The description adds value by explaining the trades parameter ('trade codes or all') and grouping location alternatives ('via prefectures and/or lat/lng+service_radius_km'), which goes beyond the schema's individual descriptions.

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 explicitly states 'Register a contractor (supply side, self-serve)', clearly indicating the verb (register) and resource (contractor). It distinguishes from sibling tools like list_contractors and match_contractors by focusing on creation. The parameter hints (trades, location) add specificity.

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 mentions the authentication requirement ('Requires Bearer API key') and provides guidance on location parameters, but does not explicitly state when to use this tool over alternatives or when not to use it. No exclusions or alternative tools are mentioned.

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