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

Annotations already declare readOnly/idempotent/non-destructive and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral guidance not in structured data: read the `purchasable` flag rather than assuming, and direct buyers to the `url`. It stops short of describing error behavior, but for a static catalog read that is minor.

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 catalog enumeration comes first, then usage/routing, then return shape — well front-loaded. It is slightly verbose and prose-heavy ('the things a record code can be carried on'), but no sentence is truly wasted.

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 output schema in play, the description must carry the return contract, and it does — key, name, description, price, `purchasable`, `url`, plus what `url` points to. Nothing an agent needs to call and interpret this tool is 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?

There are zero input parameters, so the baseline is 4 and there is no parameter semantics to clarify. The description instead spends its words on the returned fields, which is the right trade-off for a no-arg tool.

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 names the resource (the WearableDocs product line) and enumerates its members (wallet card, tag pendant, coin pendant, coin bracelet, bangle bracelet), so an agent knows exactly what a call yields. It also implicitly separates itself from get_pricing, which covers figures only.

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?

Explicit routing: 'Use this to answer what a WearableDocs code can be worn on, or which shape suits someone; use get_pricing for the figures alone and for the subscription.' The when-to-use condition and the named alternative are both stated, leaving nothing to inference.

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