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

Annotations only declare readOnly/openWorld, and the description goes well past that: it discloses a conditional data source (PA-API products when configured for the default storefront, otherwise romantic-filtered search deep-link cards plus catalogMatches) and marketplace-dependent link generation. That runtime-behavior disclosure is exactly the context an agent needs before calling.

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?

Four short sentences, front-loaded with the purpose, and every clause carries operational content. The trailing 'OpenAPI: searchAmazon' fragment is a minor stylistic wart 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 and six parameters, the description compensates by sketching the return shape (products vs. deep-link cards + catalogMatches) and the preferred fields. Remaining gaps — what catalogMatches contains and how limit affects results — are modest but real.

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%; q, locale, and marketplace are already documented in the schema, and the description largely restates the marketplace rule. It adds no meaning for the undocumented 'occasion' and 'limit' parameters, so it does not compensate for the coverage gap — baseline 3.

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 and resource — search Amazon for Valentine's / romantic gift ideas on the user's marketplace — and hints at two result modes. It does not distinguish itself from the plausibly overlapping siblings get_catalog and resolve_product, leaving the agent to infer the boundary.

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 gives strong how-to directives ('ALWAYS pass marketplace + locale for the end user', 'Prefer buyUrl / trackingTag in results') but no when-to-use versus when-not framing. An agent facing get_catalog or resolve_product gets no routing help, so usage remains 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.