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

Annotations already declare this is a safe, idempotent read. The description adds useful behavioral context beyond that: relevance values are core or related, search volume is only present once MerchantWords has finished, and broader keywords are fetched the same way.

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 short and front-loads the resource being returned. The sentence about broader keywords is slightly vague but does not waste much space.

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 read-only keyword-listing tool with no output schema, the description covers what is returned, the async readiness condition, and how to obtain the required report_id. Pagination details are left to the schema, which is reasonable.

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%; limit and cursor are described in the schema, but report_id has no schema description. The description compensates by explaining that report_id comes from list_reverse_reports, adding meaningful sourcing information.

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 clearly states the resource and scope: keywords from one Reverse ASIN report. It distinguishes itself from list_reverse_reports by pointing to report_id, but does not clarify how it differs from the sibling list_keywords tool.

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 tells the agent to pass report_id from list_reverse_reports, which implies a prerequisite flow. However, there is no explicit when-to-use or when-not-to-use guidance, and no comparison to list_keywords.

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