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

With readOnlyHint and openWorldHint already provided, the description still adds useful behavioral detail: it returns PA-API products when configured, otherwise deep-link cards with buyUrl/trackingTag plus catalogMatches. This fallback behavior is meaningful 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?

The description is front-loaded with the purpose and then covers return modes and required parameters in a compact form. The OpenAPI reference is somewhat meta, but overall it is appropriately sized and has little wasted text.

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 7-parameter search tool with no output schema, the description gives enough context: purpose, marketplace/locale requirement, and the two possible return modes. It could say more about limit behavior and budgetBand, but the core invocation needs are covered.

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 description coverage is 71%, so most parameter meaning is already in the schema. The description reinforces that marketplace and locale are required, but it does not explain budgetBand or limit semantics beyond the schema's constraints.

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 a specific verb and resource: searching Amazon for first-apartment/housewarming essentials on the user's marketplace. It is clearly a product-search tool, though it does not explicitly contrast itself with siblings like get_catalog or resolve_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?

It gives a clear operating context (search on the user's marketplace) and an explicit requirement: ALWAYS pass marketplace + locale. However, it does not state when to use this instead of get_catalog, resolve_product, or other sibling tools, leaving alternatives inferred.

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