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

No annotations are provided, so the description bears full responsibility. It details input (head circumference in cm) and output fields, implying a deterministic, read-only calculation. Could be improved by explicitly stating no side effects, but the behavioral context is sufficiently clear.

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 sentences with no extraneous information. First sentence states purpose and input, second sentence states output and related tool. Every sentence earns its place.

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 single-parameter, deterministic tool, the description is complete: it specifies input, output fields, and a reference to related tools. No gaps remain given the tool's simplicity and the lack of annotations.

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 description coverage is 0%, so the description must compensate. It adds meaning by specifying the parameter is 'head circumference (cm)', clarifying the unit and nature of the input. This fully compensates for the lack of schema descriptions.

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 the tool calculates hat size from head circumference, specifying output systems (FR/EU, US/UK, S/M/L/XL). It uses a specific verb 'calculate' and distinct resource 'hat size', differentiating from siblings by mentioning 'textile-mode' calculators.

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 explicitly states when to use the tool (calculating hat size from head circumference) and references a related tool (list_bundles) for other textile calculations, providing guidance on alternatives. Lacks explicit when-not-to-use, but adequate for a simple conversion.

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