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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful behavioral context beyond annotations: it is a pure calculation, returns an error if weight_kg is missing or invalid, and includes a medical-advice disclaimer.

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 dense but front-loaded with the core purpose, then adds standards, range context, and caveats. It is appropriately sized for a calculator tool, though the long single sentence is packed with clauses.

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 still explains what the tool returns: grams, ranges for training/weight loss/pregnancy/breastfeeding, per-meal threshold, age guide link, and error behavior. It also covers safety and medical limitations, leaving little an agent needs to infer.

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 schema already documents all three parameters. The description reinforces that the calculation comes from body weight and that age affects guidance, but it adds little semantic detail beyond what the schema provides.

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 states a specific verb and resource: calculate a person's daily protein target in grams from body weight. It also names the standards and outputs, making it clearly distinct from siblings like protein_cost, lookup_food, and compare_foods.

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?

It gives implied usage contexts (training, weight loss, pregnancy, older adults) and a clear medical caveat for kidney disease, but it does not explicitly state when to use this tool versus alternatives such as protein_cost or search_guides.

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