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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds the formulas used and the exact return keys, which is mild but real added context; it says nothing about precision, rounding, or input validation limits.

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 short sentences, front-loaded with the purpose, then the return shape and a pointer to list_bundles. Tight overall, though the return-key listing is arguably redundant against a formal output schema.

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 simple two-required-parameter calculator with full annotation coverage and an output schema, the description covers purpose, method, and return keys adequately. Only the absence of usage guidance versus sibling weight/BMI calculators is a gap.

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% (sex enum and height_cm minimum are documented), so the baseline is 3. The description adds no meaning beyond what the schema fields already convey for either parameter.

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?

States a specific verb (estimate) plus resource (ideal body weight) and even names the formulas used (Lorentz, Devine), which distinguishes it from siblings like calculate_ideal_weight_range or calculate_bmi without opening any schema.

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?

Usage is only implied by the purpose itself — an agent can infer it belongs to body-weight estimation. The cross-reference to list_bundles points at related calculators but does not say when to prefer this tool over calculate_ideal_weight_range or calculate_bmi.

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