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

Annotations already mark the tool readOnly, idempotent, and non-destructive; the description adds that it is educational only, not medical advice, and not a substitute for a clinician. It also discloses the output style ('full derivation with a PubMed citation per step'), which is important behavioral information. No contradiction with annotations exists.

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 block but efficiently front-loads the output and population, then covers output detail and disclaimers. Every sentence contributes (targets, usage, derivation, safety, contraindications). It is appropriately sized for a medical tool where disclaimers are necessary.

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 calculation tool with 11 parameters and no output schema, the description gives the essential context: what it computes, for whom, what it returns, and key exclusions. It does not describe the return structure in detail, but 'full derivation with a PubMed citation per step' indicates a detailed output. Given readOnly annotations and the absence of side effects, this is reasonably complete.

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?

The schema describes 6 of 11 parameters (weightKg, heightCm, doseMg, goalWeightKg, startWeightKg, sex) with meaningful descriptions, but the main description adds no parameter-level meaning. Parameters like age, goal, activity, medication, and weeklyLossKg rely on enum/default values or bare names, and since schema coverage is only 55%, the description should have compensated. It doesn't, leaving the less obvious parameters under-specified.

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 the exact outputs (calorie, protein, carbohydrate, fat, fibre targets plus appetite ceiling) and the population (GLP-1 receptor agonist users). It contrasts itself with standard calorie calculations, which helps distinguish it from generic calculator tools. No ambiguity remains about what the tool produces or for whom.

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 explicitly says 'Use it for anyone taking or considering one of these medications' and lists exclusions (pregnancy, breastfeeding, insulin/sulfonylurea use, disordered eating history, under 18). It does not name sibling tools as alternatives, but the inclusion criteria and the contrast with standard calorie calculations imply the right context. It could be stronger by explicitly stating when to use get_appetite_ceiling instead, but the guidance is clear overall.

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