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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context by disclosing that the tool returns multiple derived values (BMI, healthy range, BMR, calorie needs), which matters because there is no output schema. It stops short of explaining how the metric/imperial parameters interact or which inputs drive which outputs.

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 definition is short, but the leading sentence is a sample calculation rather than a purpose statement, so the front-loaded content does not tell the agent what the tool is or when to use it. The trailing web-page URL is promotional and consumes space without aiding invocation.

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?

With nine fully documented parameters, zero required inputs, and no output schema, the description does the necessary compensating work by enumerating the returned metrics (BMI, healthy weight range, BMR, daily calories). It leaves the metric-vs-imperial input convention and default behavior unexplained, which is a modest gap for a calculator with defaults pre-filled.

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 nine parameters and their enums are already documented by the schema, and the baseline of 3 applies. The description only gestures at parameter semantics through the 'kg/cm or lb/ft' phrasing, adding no detail beyond what the schema's units enum already conveys.

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 names concrete outputs — BMI in kg/cm or lb/ft, healthy weight range, BMR and daily calorie needs — and anchors them with a worked example (70 kg at 1.75 m = BMI 22.9), so an agent knows exactly what the tool computes. However, it does not differentiate itself from close siblings like bmr_calculator, tdee_calculator, and ideal_weight_calculator, which it arguably overlaps with; it never says how it differs from them.

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 pick this over the many adjacent health calculators (bmr_calculator, tdee_calculator, body_fat_calculator, ideal_weight_calculator, macro_calculator). Because the tool advertises overlapping outputs (BMR, calorie needs), the omission is actively confusing rather than merely absent — an agent cannot infer selection criteria from the text.

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