body_fat_calc

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

The only behavioral disclosure is the $0.001 USDC x402 cost, which is useful. However, with no annotations present, the description fails to disclose whether the operation is read-only, what parameters are required, what the return value looks like, or any side effects. Cost alone is insufficient.

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 compact and front-loaded, with the cost note being relevant. However, it is concise to the point of under-specification, containing only a restated name and a domain label, so it does not achieve the informative brevity of a well-written tool description.

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?

Body fat calculation is a multi-parameter task, but the description omits all required inputs, the calculation method, and the output format. There is no output schema to compensate, and the generic 'params' object provides no structure. The domain label and cost are far from sufficient for correct invocation.

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 schema's single property is a generic 'params' object described only as 'Tool parameters as JSON object', which provides no real parameter meaning. The tool description adds no parameter details, so an agent must rely on the name to guess fields like age, gender, waist, neck, and hip measurements.

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 essentially restates the tool name ('body fat calc') and adds only a broad 'Health & Fitness' category. It does not state what the tool calculates or what output it produces, and it fails to distinguish itself from sibling fitness calculators like calculate_bmi or lean_body_mass.

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 usage guidance is provided. The description gives no context about when to use this tool, what prerequisites exist, or which alternatives might be more appropriate. It does not mention any exclusions or comparisons to sibling tools.

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