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

With no annotations, the description carries the full behavioral burden and only adds the 5-free-call trial quota plus sign interpretation. It omits whether the operation is read-only, input formatting, required sample size, error behavior, and whether it computes sample or population skewness.

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 and front-loaded with the core action and interpretation. The leading 'Skewness:' label repeats the tool name, and the emoji marketing line is slightly noisy but still relevant to payment behavior.

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?

This is a simple one-parameter calculation, but critical details are missing: sample versus population skewness, the string format for values, and output expectations. The presence of a closely named sibling makes these omissions more significant.

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 0% and the single parameter is typed as a string with no description. The description says 'values array', which is ambiguous against the string type and does not explain whether values should be JSON-encoded, comma-separated, or otherwise formatted.

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 states a specific verb and resource: calculate the skewness of a distribution, and adds sign interpretation. It does not distinguish itself from the sibling x402-skewness-sample, leaving population-vs-sample skewness ambiguous.

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 only usage instruction is 'Provide values array' and a note on sign interpretation. There is no guidance on when to use this versus x402-skewness-sample or related statistics tools, and no exclusions or alternatives.

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