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

No annotations are provided, so the description carries the full behavioral burden, and it discloses nothing: not whether the result is interpolated, whether input is a list of numbers or a pre-sorted array, nor what the return looks like. Zero behavioral signal.

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 — two identical words that earn no place because they convey no information. There is no front-loaded purpose to structure.

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 three-parameter statistical tool with no annotations and no output schema, the definition is completely inadequate. Nothing about input format, scaling (0-1 vs 0-100), or expected output is communicated.

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?

All three parameters carry schema descriptions, but they are placeholders ('P to process', 'Values to process', 'Percentile to process') that convey no real meaning. Moreover, 'p' and 'percentile' appear redundant/ambiguous, and the description does nothing to disambiguate them; a nominal 100% coverage that is semantically empty does not rescue this.

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 the tautology 'Percentile: Percentile', which simply restates the tool name in both halves. It gives no verb, no resource, and no way to distinguish this from siblings such as x402-percentile-rank, x402-quartile, or x402-decile.

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 indication of when to use this tool, when not to, or which sibling covers the adjacent computation (rank vs. percentile vs. quartile). An agent has nothing to route on.

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