validate_coupon

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

No annotations are provided, so the description carries full burden. It discloses that login is mandatory and that a 401 error indicates the user is not logged in, advising a specific action. This goes beyond basic behavior. However, it does not describe what the tool returns on success or other behaviors like idempotency.

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 long, with no wasted words. The first sentence states the purpose clearly, and the second provides critical usage guidance. It is front-loaded and efficient.

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 no output schema, the description could explain what the tool returns (e.g., discount amount, validity status). It only describes validation and authentication requirements. The agent might infer return type, but it's not explicit, leaving some uncertainty.

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 does not add new meaning beyond what the schema describes for each parameter (code, token, packageCode). It only adds a note about login mandatory, which is more about usage than parameter details.

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 validates a discount coupon code for checkout. The verb 'validates' and resource 'discount coupon code' are specific. Among siblings like cancel_order or get_checkout_url, this tool uniquely handles coupon validation.

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 user login is mandatory and instructs how to handle a 401 error (prompt login via send_agent_otp). This provides clear when-to-use context. However, it does not mention when not to use it or alternatives.

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