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

With no annotations, the description carries the full burden. It discloses that the tool returns coupon codes with redemption status, implying a read-only operation. However, it omits details about pagination, default status behavior, or error handling, so it is not fully transparent.

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 with the main action front-loaded. The leading '[Buy]' is extraneous and does not contribute meaning, which slightly reduces the score, but the rest is tight and effective.

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 simple list tool with no annotations or output schema, the description covers the core action and purpose, but it does not fully explain the response format, default filters, or how limit behaves. It is adequate but leaves gaps for an agent to infer.

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 adds meaning to campaignId (target campaign) and status (redemption status), which the schema does not explain. However, the limit parameter is left undocumented beyond its schema constraints, and no other parameter details are clarified.

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 verb ('List'), resource ('coupon codes for a campaign'), and adds the distinguishing feature of redemption status. It also explains the purpose (attribution audits), which sets it apart from sibling tools like list_campaigns or create_coupon.

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?

It gives clear context for when to use the tool (cpa/cpl/cpi attribution audits) but does not explicitly mention alternatives or when not to use it. This is a clear use case without exclusions, matching the '4' criterion.

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