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

Annotations already declare readOnlyHint=true, so the tool is known to be safe. The description adds the REST API endpoint (GET /coupons), but provides no additional behavioral details such as pagination behavior, default limits, or return format. Given the annotation coverage, this is adequate but not rich.

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 concise sentence that leads with the core action and resource, then adds the REST endpoint. No word is wasted, and all information is relevant.

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?

With 4 optional parameters fully described in the schema and a readOnlyHint annotation, the description covers the essential purpose and context. The mention of the backend REST API adds a useful implementation detail. It does not explain return values, but this is typical for a list tool without an output schema.

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%, with each parameter individually described. The description's mention of 'filtering and sorting' aligns with the 'where' and 'sort' parameters but adds no new semantic meaning beyond the schema. Baseline of 3 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 a specific verb ('List') and resource ('discount coupons'), clearly distinguishing it from sibling list tools for other resources. It also mentions filtering and sorting, which further clarifies its purpose.

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 explains that it lists coupons with filtering and sorting, implying when to use it. Since no alternative coupon tool exists among siblings, explicit exclusions are unnecessary. This provides clear context without being overly verbose.

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