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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds that this is an 'estimate' using the 'US Navy' formula, which gives useful context about the method's approximate nature but does not explain output format, accuracy, or limitations.

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 phrase with zero filler. It communicates the core purpose efficiently.

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 5-parameter health calculator with no output schema and no schema descriptions, the definition is too thin. It omits important context such as the conditional requirement of hipCm for females, the expected return value (body fat percentage), and any accuracy caveats.

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%, and the description provides no parameter-level guidance. 'US Navy style' implies circumference-based inputs, but it does not explain which parameters are required, that hipCm is needed for females, or what the values represent beyond the self-explanatory schema names.

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 gives a specific resource ('Body fat') and a concrete method ('US Navy style estimate'), clearly distinguishing it from siblings like calculate_bmi or calculate_ideal_weight. It does not explicitly name alternatives, but the purpose is 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?

There is no guidance on when to use this tool versus other body-composition calculators, no prerequisites, and no exclusions. The only hint is the implied use of the tool name itself.

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