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

No annotations are provided and the description discloses no behavior whatsoever—no mention of what the tool computes, what inputs it consumes, what it returns, or any side effects. The text is entirely uninformative about the tool's runtime semantics.

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 short but this is severe under-specification, not conciseness. Repeating the tool name twice adds no informational value and wastes the opportunity to define behavior in even one substantive sentence.

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?

Despite having zero parameters, the tool's purpose is completely opaque and there is no output schema or annotation to compensate. With numerous closely named siblings (x402-percentage-change, x402-percent-of, x402-rate-of-change), the description is wholly insufficient for an agent to select or invoke this tool correctly.

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 is empty and the description adds no parameter information, but with zero parameters there is nothing to document beyond what the schema already provides. Per the zero-parameter baseline, this dimension is not penalized, although the description still fails to clarify what implicit context or mode the tool uses.

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 is purely a tautology: 'Percent Change Of: Percent Change Of' merely restates the tool name and provides no verb, resource, or operation detail. It does nothing to distinguish this tool from the many similar sibling tools like x402-percentage-change, x402-percent-change-array, or x402-percent-of.

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 no indication of when to use this tool, what problem it solves, or how it differs from alternatives. There is no mention of a preferred context, exclusions, or related tools, leaving the agent with zero routing guidance among hundreds of sibling tools.

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