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

No annotations are supplied, so the description carries the full disclosure burden, and it omits behavior such as accepted input encoding, handling of empty or non-numeric input, and the shape of the result. It does add one genuinely useful non-schema fact — five free trial calls per signed wallet — which is the sole piece of behavioral context present.

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 a short, front-loaded fragment with no filler prose, and the pricing note is at least actionable information. Brevity here reflects minimal content rather than padding, so the structural execution is fine even though the substance is thin.

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 numeric-computation endpoint with one undocumented free-form parameter, no annotations, and no output schema, an agent cannot tell how to format 'values' or what it will receive back. The description covers only identity and pricing, leaving the mechanics of invocation unexplained.

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 single parameter 'values' has 0% schema description coverage, and the description says nothing about its expected form (comma-separated string? JSON array? whitespace-delimited?) despite being typed as a plain string. With no annotations and no output schema, nothing elsewhere compensates for this gap.

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 only restates the tool name: 'Median Absolute Deviation: Median of absolute deviation' adds no verb, scope, or output information beyond what 'x402-median-absolute-deviation' already conveys. It gives no differentiation from close siblings such as x402-mean-abs-deviation, x402-quartile-deviation, or x402-iqr, all of which an agent could easily confuse with it.

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 when-to-use guidance at all — no statement of the problem this statistic solves (e.g., robust spread estimation resistant to outliers) and no comparison to the many sibling dispersion tools. The only extra sentence concerns billing, not usage selection.

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