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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive), and the description adds genuinely new behavior: a credit cost of 1 per result, failed items being free, and the absence of any login or browser requirement. That cost and auth disclosure is exactly the kind of operational detail annotations cannot express. It does not mention rate limits or pagination beyond what the schema states.

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 short sentences: the first front-loads what the tool does and returns, the second carries the operational constraints (auth, cost). No filler, no restatement of the title, and the rundown of returned fields is compact rather than belabored.

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 only two parameters and no output schema, the description's field enumeration substitutes well for a return-value contract, and the cost model rounds out the picture. Only minor gaps remain, such as whether results are deduplicated or how partial failures surface in the response.

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 100%, so both 'searches' and 'maxResults' are already fully documented, including the detail that a first page holds roughly 16-58 products. The description contributes no additional meaning about parameter semantics, which matches the baseline of 3 when the schema does the heavy lifting.

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 ('Search amazon.com by keyword') and enumerates exactly what is returned (title, price, list price, rating, review count, image, badges, URL). An agent can immediately tell this is a keyword product search rather than a review or job lookup. It stops short of naming the closest sibling (amazon-reviews) to draw the boundary explicitly.

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?

Usage is implied by the scope statement ('Search amazon.com by keyword'), and 'No login, no browser' signals a fire-and-forget call with no session prerequisite. However, there is no explicit when-to-use / when-not-to-use guidance and no pointer to an alternative tool for other Amazon data needs such as reviews.

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