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: not that the operation is a pure read-only computation, not the expected input format, and not whether output is ordered. It is not misleading, but it adds zero behavioral context.

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 text is short but structurally redundant, saying 'Five Number Summary' and then 'Five-number summary of a dataset' in the same breath. Brevity here reflects under-specification rather than efficient compression.

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?

With no annotations, no output schema, and only a one-word parameter description, the description should explain what the five numbers are, the input format, and how it relates to neighboring statistics tools. It does none of these, leaving the agent to guess at the contract.

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 100%, so the single parameter is documented in the schema, which sets the baseline at 3. However, that schema description ('Values to process') is itself thin, and the tool description does nothing to clarify the expected format (delimited string vs. list) or the ordering of values.

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 a tautological restatement of the tool name: 'Five Number Summary: Five-number summary of a dataset.' It never names the five components (min, Q1, median, Q3, max), so an agent gains no information beyond what the identifier already implies, and it does not distinguish this from siblings like x402-iqr, x402-quartile, x402-median, or x402-stats.

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, no prerequisites, and no mention of any alternative. Given the dense cluster of overlapping statistics siblings (x402-iqr, x402-midhinge, x402-range, x402-trimmed-mean), the absence of routing guidance is a real gap.

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