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

No annotations exist, so the description carries full burden, yet it says nothing about purity/determinism, minimum dataset size (quartiles need at least four points), or behavior on small/empty inputs. For an unannotated computation tool this is a significant omission.

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?

Two short clauses, front-loaded with the tool name and its definition, with no filler. The only minor waste is restating the name before the verb.

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?

No output schema exists, so return values need not be explained, and the trimean definition makes the result derivable. However, the sole input is an optional string whose encoding (comma-separated? JSON?) and minimum length are never stated, leaving an agent unable to call it reliably.

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 baseline of 3 applies, but the schema description ('Values to process') is near-vacuous and the param is typed string. The description says 'values array', which adds the notion of a numeric dataset but conflicts with the declared string type and never explains the accepted format.

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 clear verb+resource ('Calculate the trimean of a dataset') and even supplies the formula, which tells the agent exactly what statistic is produced. It stops short of differentiating from close siblings such as x402-trimmed-mean, x402-midhinge, or x402-interquartile-mean, so an agent must know statistics to pick correctly.

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?

No when-to-use, when-not-to-use, or alternative-tool guidance is given, which is a real gap in a namespace packed with median/quantile/mean variants. The trailing 'Provide values array' is a bare instruction, not selection criteria.

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