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 discloses nothing: no indication of whether this is a pure computation, what the output looks like, how ties or edge cases are handled, or whether the two parameters interact.

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?

It is short, but this is under-specification rather than conciseness — the single duplicated phrase carries no information and there is no front-loaded statement of purpose.

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 two-parameter statistical tool with no annotations and no output schema, the description leaves the agent without enough information to invoke it correctly or interpret the result.

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 coverage is nominally 100%, but the two properties are named 'value' and 'values' and described only as 'Value to process' / 'Values to process'. That is a placeholder, not a semantic distinction, and the description adds nothing to clarify which is the scored element and which is the reference set.

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 'Percentile Rank Of: Percentile Rank Of' is a pure tautology that merely restates the tool name. It never says what the tool computes or returns (e.g., the percentile rank of a value within a set of values), so an agent cannot distinguish it from siblings like x402-percentile or x402-quartile.

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 whatsoever about when to use this tool, when not to, or which sibling (x402-percentile, x402-percentile-rank, x402-quartile, x402-zscore) to prefer. The agent is left to guess from the name alone.

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