get_bestseller_rank

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description does not contradict them. It adds useful behavioral context: it costs 1 credit, returns current BSR rather than historical data, and clarifies that a lower rank means higher sales velocity. Minor gaps like error handling or missing-BSR cases are not disclosed, but the burden is lowered by 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 concise and well-structured: purpose first, then when-to-use, then alternatives, then cost. Every sentence adds value and no information is wasted.

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 simple read-only tool with two well-documented parameters and no output schema, the description provides everything needed for a correct call: what it returns, how to interpret the rank, when to use it, when not to, and cost. Nothing essential is missing.

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% — both asin and domain have full descriptions including pattern, enum, defaults, and usage guidance. The tool description adds no additional parameter-level meaning, so the baseline of 3 applies.

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 starts with a specific verb and resource: 'Get a product's current Best Sellers Rank'. It further explains what BSR consists of (numerical rank and sub-category node identifiers) and positions the tool as lightweight and single-purpose, clearly distinguishing it from siblings like get_product_detail and get_sales_history.

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 guidance is explicit: 'Use this tool when you only need the rank', with concrete examples like daily rank monitoring. It also names alternatives and the conditions for choosing them — get_product_detail when price/rating/content are also needed, and get_sales_history for historical trends.

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