Estimate body fat percentage using US Navy method.
| Name | Required | Description | Default |
|---|---|---|---|
| sex | Yes | Sex: male or female | |
| hip_cm | No | Hip circumference in cm (required for females) | |
| neck_cm | Yes | Neck circumference in cm | |
| waist_cm | Yes | Waist circumference in cm | |
| height_cm | Yes | Height in cm |
| Name | Required | Description | Default |
|---|---|---|---|
| sex | No | ||
| code | No | ||
| error | No | ||
| hip_cm | No | ||
| neck_cm | No | ||
| category | No | ||
| waist_cm | No | ||
| height_cm | No | ||
| body_fat_percent | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full burden for behavioral disclosure. It only states the method but does not mention any limitations, assumptions, or side effects. For a calculation tool, users need to know if results are approximate or based on specific formulas.
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 concise sentence, which is efficient for a simple tool. However, it lacks structure like front-loading critical info or sections. It is not overly verbose, so scores well.
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?
Given the tool has 5 parameters and an output schema, the description is too minimal. It does not explain the output or the requirement that hip_cm is needed for females, which is important for correct usage. More context would improve completeness.
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 100%, so the schema already documents each parameter. The description adds 'using US Navy method', which gives context but does not elaborate on parameter meaning beyond the schema. Baseline of 3 is appropriate.
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's purpose: 'Estimate body fat percentage using US Navy method.' The verb 'estimate' and resource 'body fat percentage' are specific, and the mention of the US Navy method distinguishes it from other health calculations among the siblings like calculate_bmi.
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 provides no guidance on when to use this tool vs alternatives. Sibling tools include calculate_bmi and calculate_bmr, which are related, but there is no mention of when body fat estimation is preferred or any prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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