createCoupon

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

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the description's claim of creating a coupon aligns. It adds value by explaining the return includes id, but does not cover authentication or rate limits. Still effective.

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 well-structured, starting with purpose, then required fields, unit details, optional fields, and references to related tools. It is slightly verbose but informative.

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 the CRUD context and annotations, the description covers creation logic, required/optional fields, unit semantics, and links to other tools. It does not mention error handling or output format beyond ID, but is sufficiently complete.

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 description explains the unit of discount_amount based on coupon_type and that delivery_charge does not require discount_amount, adding meaning beyond the schema's descriptions. However, the schema already has detailed descriptions, so the added value is moderate.

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 it creates a new shop coupon and returns the coupon object with id. It distinguishes from sibling tools by explicitly mentioning updateCoupon, deleteCoupon, getCoupons, and getCoupon for other operations.

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 specifies required fields (code, coupon_type, starts_at, ends_at) and optional fields, and explicitly tells when to use alternative tools: '変更は updateCoupon、削除は deleteCoupon、参照は getCoupons / getCoupon'.

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