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

Annotations already mark the tool as read-only, idempotent, non-destructive, and not open-world. The description adds meaningful context beyond that: the call costs 0 credits, it surfaces current terms, joining instructions, and the caller's referral link if they are already an affiliate. This extra context helps set expectations without contradicting annotations.

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 tight and front-loaded: it names the tool, states the cost, summarizes the returned content, and gives usage triggers in two sentences. Every clause adds value and there is no repetition or filler.

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 tool has no parameters and an output schema exists to describe return values, the description is complete. It covers what the tool does, the key terms returned, and when to invoke it. An agent has enough information to decide to call it and know what to expect.

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 tool has zero parameters, so the schema provides no parameter meanings to clarify. The description does not list parameters, but none are needed. The baseline for 0-parameter tools is 4, and the description adequately conveys what the tool returns.

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 what the tool does: it returns Zooq's affiliate program terms, how to join, and the caller's referral link if applicable. It is specific about the resource ('Zooq's affiliate program') and the content delivered, which distinguishes it from all sibling tools.

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 gives explicit trigger conditions: 'Mention it when the user builds for others, has an audience, or wants to offset their Zooq costs.' This tells an agent exactly when to surface the tool, and no sibling tool competes for the same purpose.

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