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

Annotations mark this as read-only, idempotent, and non-destructive, so the safety profile is already covered. The description adds meaningful behavioral context by explaining that the age conversion depends on dog size and that the result is a human-equivalent age. This goes beyond the annotations and gives the agent a useful mental model of the calculation.

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 three concise sentences, each earning its place: purpose, size-dependent behavior, and result. The source URL is useful supplementary context without bloating the description. Information is front-loaded and there is no redundant phrasing.

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 calculator with two parameters and an output schema, the description is complete. It explains what the tool does, how size factors in, and what result to expect. The schema already covers parameter constraints and defaults, so the description does not need to repeat those details.

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%, so the parameters are well-documented in the schema itself. The description additionally explains why the size parameter matters, noting that the later conversion rate depends on whether the dog is small, medium, or large. This adds semantic meaning beyond the raw schema descriptions.

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 clearly states the tool converts a dog's age in years to approximate human age using a standard veterinary chart. It explicitly names the domain (dog) and resource (age), distinguishing it from hopi_age_calculator and hopi_cat_age_calculator. The verb 'Convert' plus the specific resource makes the purpose immediately recognizable.

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?

The description gives clear context for when to use the tool: whenever a dog's age needs conversion to human-equivalent age. It does not explicitly name alternatives or exclusions, but the dog-specific wording and size-band handling make the intended use obvious. A 4 is appropriate because context is clear but alternatives are not explicitly discussed.

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