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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds only clinical scope limits, which are already credited under usage guidelines; it discloses nothing about the calculation's basis or the shape of the answer.

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 sentences, front-loaded with the use condition followed by the exclusion list. The example queries are compact and disambiguating rather than filler, so every sentence earns its place.

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?

Scope and applicability are well covered, but with no output schema the description should say what is returned (e.g. grams of protein per day) and how the value derives from weight/goal. That return-format gap leaves the definition only adequate for a calculator that produces a numeric recommendation.

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 goal, weight_kg and height_cm (including the BMI 25 adjustment) are fully documented in the schema. The description's example phrases loosely hint at weight/goal combinations but add no syntax or unit meaning beyond the schema, so the baseline 3 is appropriate.

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?

Names the specific resource (daily protein requirement) and the population (adults) with three concrete example queries, so an agent can match natural-language asks directly. It is easily distinguishable from the sibling protein_food_plan, which implies meal construction rather than a per-kilogram target.

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?

Explicitly states when to use ('an adult asks how much protein they need a day') and enumerates when NOT to use: children, pregnancy, kidney or liver disease, medical diets, and supplement/medication questions. This is a genuine when/when-not boundary, not an implied one.

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