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

Annotations already declare readOnly, openWorld and non-destructive, so safety is covered. The description adds genuinely useful operational context not in the annotations: per-request billing ($0.005), the 50-item page limit, and top-100 ranking coverage.

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?

Four compact sentences, front-loaded with the resource and ranking types, then return fields, then limits and cost. No filler.

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 no output schema, the description carries the return-value burden and does so (rank, rank change, ASIN, title, price, rating). Pagination, category scope and pricing are all covered; only an explicit alternative-tool pointer 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%, so all four parameters (page, type, country, category) are already documented, including the enum values and the category-doc URL. The description repeats the pagination/top-100 context but adds no parameter meaning beyond the schema. Baseline 3.

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?

States a specific verb (Get) and resource (Amazon rankings for a category), and enumerates the five ranking types it covers. An agent can distinguish it from search_amazon_products and amazon_product_details, which retrieve products rather than category rankings.

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 resource's nature (rankings listings), but the description gives no explicit when-to-use or when-not-to-use guidance and never names search_amazon_products as the alternative for keyword-based product lookup. Nothing is misleading, but the routing guidance is left to inference.

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