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

The description adds genuinely useful behavioral context beyond the annotations: the call costs $0.03, which an agent should know before invoking. However, 'Purchase' reads oddly against readOnlyHint=true and is not clarified, and nothing is said about what an exact match returns (boolean, confidence, notice payload).

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?

It is a single short sentence with no wasted words, and the cost is front-loaded. But it is terse to the point of under-specification, so brevity here is not purely a virtue.

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?

The input is a one-string schema and the annotations already declare read-only, idempotent, open-world behavior, so little more is strictly needed. The remaining gap is what a 'match result' contains and how tokens are sourced, which the description leaves implicit.

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 single required parameter product_token has 0% schema description coverage, and the description does not explain what a token is or how to obtain one (presumably from resolve_consumer_product). With one undocumented parameter, the description fails to compensate for the schema gap.

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 (an exact CPSC recall-notice match result), which is more specific than a bare tautology, but 'Purchase' is a confusing verb for a read operation and no scope or product is mentioned. It also does not distinguish this from siblings build_product_recall_evidence or resolve_consumer_product.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives, despite two closely related sibling tools existing. The only implicit cue is the price, which hints at a paid lookup but does not say when it is warranted over the cheaper/different siblings.

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