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 the calculation methodology (AAHA) as useful context, but reveals nothing about limits, edge cases (e.g. very old dogs), or validation behavior.

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?

Four short sentences, front-loaded with the core conversion, no filler in the main explanation. The trailing list_bundles pointer is the only sentence that arguably doesn't need to be here.

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 annotations carrying the safety profile and an output schema existing, the description needn't explain return values, yet it still notes the return. It is complete enough for a simple two-parameter read-only calculator, with only usage-boundary detail missing.

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% with only 2 parameters, so the schema already documents 'dog_years' and the 'size' enum. The description loosely restates them as 'dog age years, breed size' without adding format, unit, or default ('medium') information, so baseline 3 applies.

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 ('Convert dog age to human-equivalent years') and names the method (AAHA), so an agent can distinguish it from calculate_cat_age or calculate_pet_age without opening the schema. It stops short of explicitly naming those alternatives, which keeps it out of the top band.

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?

'Use for canine health monitoring' gives an implied use case but no when-not conditions and no explicit pointing to sibling age calculators (calculate_cat_age, calculate_pet_age) that an agent might confuse it with. The pointer to list_bundles is a discovery hint, not invocation guidance.

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