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

Beyond the readOnlyHint annotation, the description explicitly discloses behavioral traits such as 'no subscription by the agent' and 'we do not have card data', providing additional transparency about what the tool does not do. No contradictions with 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 a single, concise sentence that front-loads the main action ('returns payment rules') and then lists the specific rules. It is not verbose and effectively communicates all necessary information in a structured manner.

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?

Since there is no output schema, the description adequately explains what the tool returns: the payment rules, including their contents. This is sufficient for an agent to understand the tool's output and use it correctly without additional context.

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 input schema has zero parameters, so there is nothing to describe. According to the rubric, a baseline of 4 is appropriate for 0 parameters. The description does not need to add any parameter information.

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 returns payment rules for donations, listing specific content such as 'donation is not a purchase', 'refund within 14 days', and 'no card data'. This unambiguously defines the tool's purpose and distinguishes it from siblings like catalog or preparation 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 does not provide any explicit guidance on when to use this tool versus alternatives. It only states what it returns, leaving it to the agent to infer that it is for retrieving donation rules. No when/when-not conditions are mentioned.

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