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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safe read-only profile is covered. The description usefully adds the WHO threshold values (0.90 / 0.85), which is real interpretive context, but it does not say how the result is classified or returned.

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?

Three short sentences, front-loaded with a concrete worked example, then the input instruction, then a reference URL. Efficient, though the trailing web-page link adds little for tool selection.

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?

There is no output schema, so the description would ideally indicate what is returned (the ratio and its classification). It partially compensates by naming the WHO thresholds, but leaves the output shape to inference.

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% with all six parameters documented, so the schema carries the burden and a baseline 3 applies. The description adds the cm/inches unit distinction but does not clarify which WHO threshold pairs with the sex enum.

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 states a specific verb+resource: it computes a waist-to-hip ratio, illustrated with a worked example (86 cm waist / 100 cm hips = 0.86). An agent can tell what the tool produces. It does not, however, differentiate itself from health siblings like bmi_calculator or body_fat_calculator.

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?

"Enter your measurements in cm or inches and compare with the WHO thresholds" implies the input flow and the interpretation step, but offers no explicit when-to-use guidance or exclusions relative to the many other body-metric calculators. Usage is only implied.

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