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

Goes well beyond the readOnly/idempotent/openWorld annotations: it discloses the sign-in requirement, the country precedence chain (explicit > saved account > host hint), the fallback of asking the user, and the refresh semantics of re-calling with identical arguments. These are exactly the operational traits an agent cannot infer from annotations.

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?

Purpose is front-loaded in the first sentence and every subsequent sentence carries functional information (auth, ID constraints, country logic, refresh, alternative tool). It is dense but not padded; the length is justified by the amount of conditional behavior, though it could be trimmed slightly.

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 two-parameter read tool with an output schema, the description covers everything an agent needs: auth, ID constraints, country resolution, refresh behavior, and the sibling to call for buy links. The return payload is only briefly summarized, but an output schema exists so that is appropriate.

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 description coverage is 0% and the enum country field has no per-value documentation, so the description must compensate; it does so by defining country precedence rules, the fallback when unset, and how to persist a choice, plus constraining styleId to catalog IDs only. This adds substantial meaning beyond the raw schema.

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 verb and resource ('Find matching products and retailers where the user can buy a catalog style') and its scope is clearly distinct from sibling style-purchase-buy-url, which it explicitly routes to for buy links. An agent can separate it from style-ways-to-wear-by-id and style-wear-with-get-by-id without opening any 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?

Provides explicit preconditions (requires sign-in, exact catalog styleId, userStyle IDs unsupported), resolution rules for the country parameter, and named alternatives/prerequisites (update-user-settings-tool for saving, style-purchase-buy-url for buy links, re-call to refresh). It also states what the agent should do when no country is available.

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