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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint and destructiveHint=false, and an output schema exists, so the safety and return-shape burden is largely covered. The description adds genuine context the annotations lack — U.S.-only coverage and that results are live/current — but says nothing about pagination, rate limits, or freshness lag. Under rich annotation coverage this is a moderate, not exceptional, contribution.

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 compact sentences, front-loaded with the use case before the exclusion, and the return-shape note last. No filler or restatement of the title.

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 read-only search tool with an output schema and full annotation coverage, the description supplies everything missing from structured fields: region scope, liveness of the deals, and the sibling routing rule. Remaining gaps (pagination, sorting behavior) are covered by the schema's defaults and bounds.

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 60%, with query and category documented in-schema; the description only restates the brand/category axis implicitly. It adds nothing for sort, limit, or min_discount_percent, so it neither compensates for the coverage gap nor detracts.

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?

Specific verb (discover/compare) paired with a specific resource (current U.S. gift-card discounts) and scope (across brands or within a category). It explicitly names the sibling it is not, so an agent can separate it from get_gift_card_deals without opening either 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 both a when-to-use condition (discover or compare across brands/categories) and a when-not-to-use condition (exact single brand), naming the alternative get_gift_card_deals as the fallback. Nothing about routing is left to inference.

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