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

Annotations already establish readOnly/idempotent/non-destructive, so the bar is lower; the description adds genuinely useful context beyond them: prices are in US cents and dollars, they reflect what checkout actually charges, and only settled (non-provisional) prices are exposed. It does not cover pagination or response shape, but the core behavioral caveat about not inferring prices is valuable.

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?

Three sentences, each doing work: what is returned, the units and authoritative source, and the anti-inference guardrail. The core content is front-loaded and there is no filler.

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 no parameters and no output schema, the description carries the full burden of describing the return payload, and it does so by naming each price category. An agent has everything needed to call it and interpret the results.

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 tool takes zero parameters, so the baseline is 4 by rule. The description correctly implies a parameterless, whole-catalog read, adding no misleading parameter expectations.

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 resource ('Every WearableDocs price') and enumerates exactly what is returned: yearly subscription for the first and each additional household member, one-time wearable costs, and the printed wallet card. This scope statement, plus the caveat about only settled prices, clearly separates it from the product-listing sibling get_products.

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?

Gives an explicit exclusion rule: 'never quote a price for anything this tool does not return, and never infer one from a product name,' which tells the agent when NOT to rely on it. It stops short of naming a specific alternative tool for cases where a price is missing, so it falls just short of full routing guidance.

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