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

The annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. On top of that the description discloses the return shape (search links plus hand-picked catalogMatches with /dp links) and an important non-obvious behavior: marketplace resolution is forgiving and "Never an error when missing." That is real added context beyond the annotations.

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 short sentences: purpose first, then the most consequential parameter guidance, then what comes back. The trailing "OpenAPI: searchAmazon" is a compact provenance tag rather than filler, and no sentence is redundant.

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 takes on the burden of describing the response and does so (search links plus catalogMatches with /dp links). It also covers marketplace resolution end-to-end. Gaps remain around the filtering parameters (giftCategory, ageBand, occasion) and result limits, which an agent must derive from the enum values alone.

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%, so several parameters carry their own documentation. The description reinforces the marketplace parameter (accepted values, defaults, fallback order) and ties locale to English responses, but says nothing about giftCategory, ageBand, occasion, or limit, leaving those to the enum values and defaults. This is a standard baseline-3 case.

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 gives a specific verb and resource ("Search birthday gifts on the user's Amazon storefront") and names the underlying OpenAPI operation (searchAmazon), so an agent can tell it apart from get_wishlist or add_wishlist_item. It does not explicitly contrast with the closer siblings get_catalog and resolve_product, so the differentiation is implicit rather than stated.

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 concrete guidance on choosing the marketplace argument (amazon.com for US/English, amazon.se for Sweden) plus the fallback chain when it is omitted. However, the description never says when this tool should be chosen over get_catalog or resolve_product, which also surface product data — the agent must infer that from the names alone.

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