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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered without the description. The description adds that it returns upcoming dates and vaccines, though that is largely duplicated by the output schema, and it introduces a behavioral inaccuracy by claiming a 'last vaccine date' input that does not exist.

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?

Short, front-loaded, and the purpose lands in the first sentence. 'Use for pet care planning' and the returns sentence carry little weight given the output schema already exists, but there is no padding or bloat.

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, return values need not be described, and annotations cover safety, so the remaining burden is small. The description is adequate on purpose but incomplete/inaccurate on inputs (phantom 'last vaccine date') and silent on assumptions behind the schedule (which vaccines, over what horizon).

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 coverage is 100% and both real parameters (pet_type enum, birth_date YYYY-MM-DD) are fully documented, so the description adds nothing for them. Worse, it lists 'last vaccine date' as an input when the schema has only two properties, which actively misleads an agent about the required argument set.

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?

States a specific verb+resource ('Generate upcoming vaccination schedule for a puppy or kitten') with the scope restricted to young animals, which separates it from pet siblings like calculate_pet_age or calculate_pet_bmi. It does not, however, explicitly position itself against the closest-sounding sibling, calculate_dog_pregnancy, which also produces date sequences for pets.

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?

Offers only 'Use for pet care planning', which is generic context rather than a decision rule, and gives no when-not guidance. The pointer to list_bundles is a discovery cross-reference, not a named alternative for overlapping cases, so usage is implied at best.

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