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

No annotations are present, so the description carries the full behavioral burden. It discloses that the tool returns the WHO weight category and healthy BMI range, and it states the x402 price per call, which is useful operational context. It does not describe side effects, but 'Calculate' strongly implies a pure read-only computation.

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 two tightly packed clauses: the calculation and its outputs come first, followed by the pricing detail. There is no filler, and the most important information is front-loaded.

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 no output schema, the description must explain what is returned, and it does so by naming the WHO category and healthy range. It could be more complete by specifying the response structure or field names, but for a simple two-parameter calculator it is nearly sufficient.

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%, and both parameters already specify units '(kg)' and '(cm)'. The description repeats those units but adds no new syntax, constraints, or edge-case meaning beyond the schema, so the baseline score of 3 applies.

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 verb (Calculate), resource (Body Mass Index), required inputs (weight in kg, height in cm), and additional outputs (WHO category, healthy BMI range). This is enough to distinguish it from the many sibling converters and calculators without opening the 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?

The description implies the tool is used whenever BMI is needed and clearly lists the required inputs, but it provides no explicit when-to-use vs. when-not-to-use guidance and names no alternatives. The context is adequate but not enriched with routing information.

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