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

With no annotations, the description carries full disclosure responsibility. It does reveal the output formula and asks for a values array, but it omits edge-case behavior, whether the array must be sorted, quartile interpolation method, and handling of empty or non-numeric input. It is minimally transparent but not detailed.

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 two sentences with no filler and front-loads the calculation purpose before the output definition. The leading 'Iqr:' label is slightly redundant but does not meaningfully hurt clarity.

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?

The core contract—input array and output formula—is present, and there is no output schema to rely on, so the description must carry return-value detail. However, it leaves out important practical details such as numeric types, sorting requirements, and edge cases, and the empty schema makes the promised values-array input undocumented in the structured definition.

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 input schema has zero properties, so the description is the only source of parameter meaning. It clearly states that a values array must be provided and defines what the array is used for. It could add type constraints (numeric) and sorting expectations, but for a zero-param schema this is strong compensation.

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 uses a specific verb ('Calculate') and resource ('interquartile range of a dataset') and defines the result as Q3 minus Q1, distinguishing it from sibling statistical tools like quartile or percentile. The formula removes ambiguity about what an agent will receive.

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 about when to choose this tool over alternatives such as get_stats, quartile, percentile, or interquartile-mean. The only implied use case is needing an IQR, which the name and description make obvious, but no explicit when/when-not or alternative selection advice is provided.

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