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

Annotations already carry the safety profile: readOnlyHint=true, idempotentHint=true, openWorldHint=true, destructiveHint=false. The description is consistent with these and adds the output substance (top ASINs by sales rank) but little else beyond what the annotations and purpose statement convey. No contradiction with 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?

One purpose sentence plus a concrete example, with the core function front-loaded. The example is genuinely useful for showing required vs optional args. Slightly longer than strictly necessary due to the example, but the example earns its place.

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 bestsellers query with rich parameter schema and safety annotations, the description plus schema cover what an agent needs to call it. It does not describe return format or result limits, but with no output schema and a simple list use case, the gap is minor.

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 the schema already documents all three parameters well, including domain defaults and how to obtain a category id via keepa_product. The description itself adds no parameter detail beyond the inline example, so the baseline 3 is appropriate.

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 states a specific verb and resource: 'returns the top ASINs by sales rank for a given category node id'. This clearly distinguishes it from siblings like keepa_product (single product details) and keepa_search (keyword search). The worked example reinforces the exact call shape.

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 implies when to use it (when you have a category node id and want top ASINs by rank) but never explicitly says when not to use it or which sibling to prefer instead. The schema's category parameter does cross-reference keepa_product for finding a category, which adds some routing guidance, but the description itself offers no exclusions.

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