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

Annotations already cover readOnly and openWorld, so the description isn't responsible for the safety profile. It goes beyond them usefully by disclosing best-effort relevance behavior and the concrete failure mode: an obscure keyword returns the storefront's own fallback recommendations rather than an empty result.

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?

Two sentences, no filler. The scope statement (which brands, what returns) leads, and the caveat about fallback results follows. Dense but front-loaded; the parenthetical brand instruction sits mid-sentence where it is still readable.

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 3-parameter search with an output schema covering return values, the description supplies the missing pieces: brand semantics with default, and the relevance/fallback behavior. Pagination is left to the schema's page description, which is a minor omission rather than a gap.

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 coverage is 100%, so the baseline is 3, but the description adds genuinely new information: the brand field supports four storefronts and defaults to Old Navy, which the schema's enum-ish description ('on, gap, br, at') never states as a default.

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 (Search) and resource (product listings) across four named storefronts, and describes what comes back: normalized product summaries with pricing, review scores, and color variants. This clearly separates it from sibling detail tools like oldnavy_product or oldnavy_category without needing to name them.

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 explains the brand selector and its Old Navy default, which steers storefront choice, and the fallback note sets expectations. However, it never says when to prefer this tool over oldnavy_category, oldnavy_categories, or oldnavy_product, so usage is implied rather than explicit.

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