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

Annotations already declare readOnly and openWorld, so the safety profile is covered; the description adds genuinely new behavior — the no-input default, the amazon.com curated-ASIN downgrade to English search links, and the two supported storefronts. It omits error behavior for invalid ASINs/URLs, but the added disclosure is substantive.

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 tight, front-loaded sentences that each carry information; the input forms lead, then the amazon.com nuance, then the fallback. The trailing "OpenAPI: resolveProduct" is an internal artifact that earns little for a calling agent.

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 9-parameter, zero-required tool with no output schema, the description covers the primary inputs and the return concept (buyUrl) but leaves the optional filtering parameters and the shape of the response largely unexplained. Adequate to call, not enough to call optimally.

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 67%, and the description contributes real meaning by framing url/asin/keywords as alternative input paths and describing the no-input default. However, two parameters (ageBand, preferSearch) remain undocumented in both schema and description, and the interplay of category/ageBand with keyword search is unexplained.

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?

Uses a specific verb (resolve) with a defined output (buyUrl) and enumerates the accepted input forms (ASIN, /dp/ URL, keywords). It is distinguishable from siblings like search_gifts and get_catalog by being a resolver of a specific reference into a storefront link, though it never names those siblings to sharpen the contrast.

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 implicit routing rules: supply ASIN, URL, or keywords, and with no input it falls back to a default kids gift search. It never states when to prefer this over search_gifts or get_catalog, nor whether the input forms are mutually exclusive, so the agent must infer the selection conditions.

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