list_coupons

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

The annotation already declares readOnlyHint=true, so the safety profile is known. The description adds the 'all coupons' scope and 'usage counts' as return context, but it doesn't discuss pagination, performance, or other behavioral constraints beyond that. This is modest extra context, appropriate for a simple read-only list.

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 sentence with no filler, front-loading the verb and resource. Every word contributes meaning.

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 zero-parameter, read-only listing tool with no output schema, 'List all coupons with usage counts' conveys the essential behavior and the key return field. It is complete enough for an agent to select and invoke the tool 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?

With zero parameters, the schema is empty and there are no parameter meanings to clarify. The description's 'all coupons' confirms no filtering is possible, which aligns with the empty schema. The baseline of 4 for zero-parameter tools is appropriate.

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 uses the specific verb 'List' with the resource 'coupons' and adds scope ('all') and output detail ('with usage counts'), clearly distinguishing it from sibling coupon mutations like create_coupon and delete_coupon. It leaves no doubt about what the tool does.

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 phrase 'List all coupons' provides clear context: use this tool to retrieve all coupons. It doesn't explicitly mention when not to use it or name alternative tools, but for a simple list operation the intended usage is self-evident.

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