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

Annotations already establish read-only, non-destructive, non-idempotent behavior, and the description adds genuinely useful context beyond them: per-call credit cost, the fact that repeated calls may charge again (reinforcing idempotentHint=false), and a data-trust warning. It stops short of describing return shape or rate limits, but the added cost/trust context is valuable.

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?

Three tight sentences: purpose first, then billing, then trust. No redundancy, and the most important clause (what the tool does) is front-loaded.

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 should ideally convey the shape of the returned distribution, but it only names it. Cost and trust caveats are covered, and all six parameters are documented in the schema, so the definition is callable, but the return-value gap leaves it merely adequate.

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 conveys parameter meaning (including the note that newProduct is a no-op and returnFields is optional). The description adds no parameter-level detail, which is the correct baseline 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?

States a specific verb and resource ("Retrieve ratings-count distribution for a category"), which is clearly distinguishable from most siblings. However, it does not distinguish itself from the very similar sibling amazon_market_rating (singular), leaving ambiguity about which rating tool to pick.

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 gives no when-to-use guidance, no prerequisites, and never names or contrasts with alternatives like amazon_market_rating or amazon_product_node. The only usage-adjacent content is billing cost, not selection guidance.

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