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

With no annotations, the description carries the full burden, and it discloses almost nothing behavioral beyond the pricing/quota line ('5 free trial calls per signed wallet'). It does not state input format, error behavior, precision, or what happens with fewer than four values.

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?

One sentence that front-loads the name and the defining formula, followed by a short quota note. Efficient, though the emoji and trial-call pitch are marketing padding rather than task-relevant content.

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 stats tool with no annotations, no output schema, and an undocumented input parameter, the description should at minimum explain the accepted input format. It defines the math but leaves the actual invocation contract unstated.

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 'values' parameter has no schema description (0% coverage) and the description never mentions it or its expected format (comma-separated string vs. JSON array). The formula references Q1/Q3 but gives no hint about how the data series is supplied.

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?

States a specific verb ('Returns') and a precisely defined resource: half the interquartile range, spelled out as (Q3 - Q1) / 2. The formula effectively distinguishes it from sibling tools like x402-iqr or x402-quartile, though it never names them explicitly.

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 on when to use this instead of the many nearby dispersion tools (x402-iqr, x402-interquartile-mean, x402-median-absolute-deviation). The only usage-adjacent text is the pricing note about free trial calls, which is billing context, not selection guidance.

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