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

Annotations already declare readOnly, idempotent, non-destructive and non-open-world, so the safety profile is covered. The description adds the return shape (kcal_per_day), but since an output schema exists this is largely redundant and it says nothing about units of the input weight or how the lifestyle/indoor default is treated.

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 short sentences with the core purpose front-loaded and no padding. The trailing cross-reference to list_bundles is marginally useful rather than wasteful.

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 simple three-parameter calculator with a read-only annotation set and an output schema, the description is close to sufficient. The residual gaps are the loose 'lifestyle' vs 'indoor' mapping and the absence of input units, which an agent would need when constructing the call.

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 0%, so the description must carry the burden. It loosely maps its three drivers to the three parameters ('weight, age and lifestyle'), but 'lifestyle' does not match the actual 'indoor' boolean, the unit for weight_kg is unstated, and the enum values for age are left entirely to 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 concrete verb and resource ('Calculate daily cat food quantity') and names the three inputs that drive it, so the agent knows exactly what it computes. It does not, however, distinguish itself from nearby siblings such as calculate_dog_food or calculate_pet_food_portion, which share nearly the same phrasing.

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?

There is no statement of when to pick this tool over calculate_pet_food_portion, calculate_dog_food, or calculate_cat_age. The only routing hint ('See list_bundles for related animaux calculators') points at a discovery tool, not at an alternative calculator, so it does not resolve the selection question.

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