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

No annotations are provided, so the description bears full behavioral disclosure burden, but it discloses nothing. It does not state what the tool computes, how it receives an array, whether it is read-only, what it returns, or any edge-case behavior.

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 text is minimal in length, but brevity here is under-specification, not conciseness. A single repeated phrase contains no useful content and fails the basic requirement that every sentence 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?

For a tool with no annotations, no output schema, and no parameter schema, even the tool name is ambiguous. An agent cannot know what array is expected, what percent-change formula is used, what format the result takes, or how to invoke this correctly. The description is completely inadequate.

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 with 0 params the baseline is 4. The description does not add parameter enrichment, but there are no parameters to document. The main uncertainty about how the array is supplied falls under behavioral transparency, not parameter semantics.

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 a bare tautology: 'Percent Change Array: Percent Change Array' restates the tool name without any verb, resource, or differentiation from similar tools like x402-percentage-change or x402-percent-change-of. It provides zero actionable meaning.

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 guidance exists for when to select this tool over siblings. There is no mention of arrays, input expectations, or any alternative tools, leaving the agent completely without routing information.

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