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

No annotations are provided, so the description carries the burden of behavioral disclosure. It communicates this is an estimation/calculation tool and names the outputs (body fat and lean body mass). However, it does not disclose method limitations, accuracy caveats, or that hip measurement is only required for females, which is a notable behavioral nuance.

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, front-loaded with the method name and primary purpose. Every phrase adds value: method, what it estimates, inputs, and outputs. No wasted words or redundancy.

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 calculator with no annotations and no output schema, the description covers the core purpose, inputs, and outputs. However, the female-only hip requirement and the use of centimeters (implied only by schema property names) are missing, which are important contextual details for correct use.

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?

With 0% schema description coverage, the description compensates by enumerating most parameters in plain English (sex, height, neck, waist, hip). It fails to explain the hipCm parameter is conditional on sex and omits weightKg entirely, which leaves a partial gap in parameter understanding.

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 estimates body fat percentage using the US Navy tape-measure method, with a specific verb ('Estimate') and resource ('body fat percentage'). This distinguishes it from sibling calculators like ideal_weight_calculator or tdee_calculator, which target different health metrics.

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 clearly conveys when to use the tool (when body fat percentage is needed via the Navy method) and lists the required inputs. It does not explicitly exclude alternatives, but the method name and input list provide enough context for a knowledgeable agent to select it over sibling calculators.

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