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

With no annotations and no meaningful description, the tool's actual behavior is completely undisclosed. The text only repeats the phrase 'Percentage Change' and gives no indication of side effects, return values, defaults, or any other behavioral trait.

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 under-specification rather than useful conciseness. Repeating the tool name in a label-like format wastes the only available space and does not earn its place as a functional description.

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?

For a tool nested among hundreds of similarly named math and percentage tools, this description is wholly inadequate. It provides no information about the operation, required arguments, return format, or relationship to neighboring tools, so an agent cannot reliably select or invoke it.

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 the baseline is 4; there are no parameter semantics for the description to clarify. However, the description itself adds nothing meaningful about the tool's expected inputs.

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 tautological: 'Percentage Change: Percentage Change' merely restates the tool name and provides no verb, resource, or operational meaning. It does not say what the tool computes, expects, or returns, and it does nothing to distinguish it from siblings like x402-percent-change-of or x402-percent-change-array.

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, what inputs are needed, or how it differs from related tools. The description offers no context, prerequisites, or alternative routing, leaving an agent completely without direction.

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