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, and it fails to do so. It reveals nothing about the output ratio format (e.g., 'N:M', decimal, or simplified fraction), how invalid or out-of-range inputs are handled, or how the tool receives its input value at all.

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 short sentence, which is appropriately sized, but the 'Percent To Ratio:' prefix is fully redundant with both the tool name and the following clause 'Convert percent to ratio.' It is concise but contains filler that does not earn its place.

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?

The tool is simple but the description leaves critical gaps unaddressed: with an empty input schema, it is unclear how the percent input is provided, and without an output schema, the expected ratio representation is ambiguous. An agent cannot be confident whether calling it returns '1:2', '0.5', or '50:100'.

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?

With zero parameters in the input schema, the baseline is 4 per the rubric. The description adds no parameter-level detail, but there is nothing to document since the schema is empty. Notably, the description also fails to clarify how the percent value is supplied, though this is a schema-level oddity rather than a parameter-semantics gap.

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 'Convert percent to ratio' restates the tool name x402-percent-to-ratio almost verbatim, with the 'Percent To Ratio:' prefix merely repeating the title. It supplies the verb 'convert' and a resource, but adds no information beyond what the name already encodes, making it a near-tautology.

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?

There is no guidance about when to use this tool versus alternatives. The sibling list contains closely related tools (x402-ratio-to-percent, x402-fraction-to-percent, x402-percent-of, x402-percentage-change), but the description makes no attempt to differentiate this tool from them or indicate the conditions that would select it.

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