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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is added context, and it delivers: the formula's source ('2025 joint advisory'), the range derivation from body weight, and that results are split into per-meal amounts matching MALAI's calculator. It stops short of noting the GLP-1 framing's limits or rounding behavior, but the methodology disclosure is well beyond the annotations.

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?

It is front-loaded with the verb, formula, and output shape in a single dense sentence, followed by example triggers and one exclusion clause. Every element earns its place; nothing is repeated from the schema or annotations.

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 an output schema present, the description needn't explain return values, and the annotations fully carry the safety profile. The remaining gaps for a two-required-param calculator – method, scope, unit handling implied by the 210 lb example, and sibling routing – are all covered.

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 baseline is 3; the schema already documents weight, weight_unit, and meals_per_day with enum and bounds. The description reinforces that weight drives the g/kg computation and that meals_per_day spreads intake per meal, but adds no syntax, default value, or edge-case meaning beyond the schema.

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+resource ('Calculate a daily protein range') and states the exact method (1.2–1.6 g/kg, 2025 joint advisory, split per meal). It explicitly names the sibling it is not (malai_get_nutrition_targets), so an agent can separate it from the other nutrition tools without opening a 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?

It supplies concrete trigger utterances ('how much protein should I eat on Zepbound', 'I weigh 210 lb, what's my protein target') and an explicit exclusion routing signed-in saved targets to malai_get_nutrition_targets. Both the when and the when-not are stated outright.

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