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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It says nothing about what the tool computes, whether it is a pure calculation, what units it expects, or what it returns.

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 two repetitions of the same phrase, providing no information and wasting the only line available. It is not merely terse; it is devoid of content.

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 no annotations, no output schema, and a single parameter, the description should explain that this computes the Rule of 72 (a finance formula for doubling time). It does not, leaving the agent unable to know even the basic purpose.

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% and there is only one parameter ('rate') with a schema description of 'Rate to process'. Per the rules, high schema coverage with no param info in the description yields a baseline of 3.

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 'Rule Of72: Rule Of72' is a tautology that merely restates the tool name. It does not state a verb, the resource being computed, or what the tool returns. A sibling like x402-rule-of69 provides no differentiating context either.

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?

No indication of when to use this tool, what inputs are appropriate, or how it differs from related finance tools such as x402-doubling-time or x402-compound-interest. There is no guidance whatsoever.

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