median

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

With no annotations, the description must disclose behavior, and it does note that strings convertible to numbers are allowed while comma formatting is not. However, it omits edge-case behavior such as handling of empty arrays, even-length medians (whether it averages the two middle values), and what happens with non-numeric strings. Thus, it provides some transparency but leaves important behavioral gaps.

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 a single, front-loaded sentence that states the core function immediately, followed by a brief, relevant constraint. No unnecessary words or repetition.

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?

While the description conveys the primary operation and input type, it does not address return value details or edge cases like even-length arrays or invalid input behavior, which are relevant for a mathematical function. Given there is no output schema, this information would be valuable, leaving some ambiguity for an agent invoking the tool.

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 contains zero parameters, so the description carries the burden of explaining the tool's input. It specifies 'Array of numbers' and additional constraints on string formatting, which is meaningful given the empty schema. This earns above baseline because it compensates for the lack of parameter documentation, even though there are no parameters to document.

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 clearly states 'Calculates the median from an Array of numbers' with a specific verb and target, distinguishing it from sibling tools like average and mode. It also clarifies the expected input type, making the purpose unambiguous.

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?

The description implies usage by specifying that arrays of numbers are expected and that strings convertible to numbers are allowed, but it does not explicitly contrast with alternatives such as average or mode. The comma limitation provides a conditional 'when not to use' but no direct sibling differentiation.

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