calculate_age_in_units

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

No annotations are provided, so the description must cover behavioral aspects. It only says the tool calculates age and returns an object, but does not disclose input validation, timezone handling, error cases (e.g., future dates), or that it is a read-only operation.

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 two concise sentences with no fluff. The first sentence clearly states the purpose and the second sentence directs to related tools.

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?

Given the tool's simplicity (one parameter, returns an object), the description covers the essential action and output. However, it lacks context on edge cases, error handling, and a clearer differentiation from similar sibling tools, which would be helpful given the vast number of calculators.

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?

The input schema describes the only parameter (birth_date) as 'Birth date YYYY-MM-DD' with 100% coverage. The description does not add any extra meaning beyond what the schema already provides, so baseline score of 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 uses a specific verb ('Calculate') and resource ('exact age in multiple units'), and lists the output fields (weeks, hours, minutes, seconds). It distinguishes itself from sibling 'calculate_age' by specifying 'multiple units' and mentioning related fun calculators via list_bundles.

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 only hints at related fun calculators via list_bundles but does not explicitly state when to use this tool versus simpler alternatives like 'calculate_age'. No when-not or prerequisite guidance is provided.

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