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

No annotations are provided, so the description carries the full burden, and it does disclose the non-obvious behavioral facts: only the wallet card is purchasable, engraved hardware has no price, and the subscription requires buying none of it. It says nothing about auth or error behavior, but for a zero-param read of a static catalog that risk is minimal.

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?

Front-loads the core answer (what a code can be carried on) before the return fields and the purchasing caveat. The carrier enumeration is somewhat list-like, but each item is the actual content of the response, so it earns its space.

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?

No output schema exists, and the description compensates by naming the returned fields and their meaning (purchasable flag, price present only where settled). Combined with the purchasability caveat, an agent has everything needed to call and interpret this tool.

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; there is no argument syntax for the description to clarify. The description does explain the shape of the returned payload, which is the closest thing to parameter semantics available here.

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 (the carriers a WearableDocs code can live on) and enumerates them concretely, then names the fields returned (key, name, description, purchasable, price). It explicitly distinguishes itself from the sibling get_pricing, so an agent can route without opening a schema.

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 when-to-use call ("Use this rather than assuming anything is for sale") and names the alternative for an adjacent need ("get_pricing for what the subscription costs"). The condition that selects each tool is unambiguous.

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