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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful behavioral context — the output always includes a buyUrl and trackingTag is null until enrollment — but says nothing about failure modes (invalid ASIN, wrong marketplace) or rate/network behavior of an open-world lookup.

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 tight sentences with the operation up front and the required-parameter rule second. The trailing "OpenAPI: resolveProduct" is mild filler but costs little.

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, the description does well to say the result is a buyUrl with a trackingTag field. However, for an 8-parameter tool with three undocumented optional params and no return-shape detail beyond a single field, the description leaves real gaps.

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 63% and the description reinforces the two required params and the three input selectors (url/asin/keywords). It adds nothing about occasion, giftCategory, or budgetBand — budgetBand has no schema description at all — so those optional refinement parameters remain opaque.

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 (resolve) and the accepted input forms (ASIN, /dp/ URL, keywords) plus the output (buyUrl), so the operation is unambiguous. It does not explicitly differentiate itself from siblings like search_gifts or get_catalog, which is the only thing keeping it from a 5.

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?

"ALWAYS pass marketplace + locale" gives a clear invocation requirement, but there is no guidance on when to choose this over search_gifts or get_catalog, or when keywords vs ASIN vs url is appropriate. Usage is implied by the input forms rather than stated as a decision rule.

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