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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no additional behavioral context such as rate limits, authentication requirements beyond the API key (which is in the schema), or any edge cases. It does not contradict annotations but also does not enrich behavioral understanding beyond what the annotations provide.

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 a single, dense sentence that front-loads the core function, followed by a concrete example. There is no fluff or redundant wording. Every phrase adds value, and the structure is easy to parse.

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?

Given the tool has four parameters all documented in the schema, no output schema, and comprehensive annotations for safety, the description is complete. It enumerates the data points returned and provides an example call. Nothing an agent needs to invoke it correctly 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 are documented in the schema. The description adds an example showing typical usage, which reinforces the meaning but does not introduce new semantics. With full schema coverage, the baseline is 3, and the description does not exceed that.

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 tool's purpose: retrieving price & sales-rank history and stats for a specific Amazon ASIN, listing specific data points like historical low/high/avg, current prices, sales rank, and estimated monthly units sold. This distinguishes it from sibling tools like keepa_search, keepa_deals, and keepa_bestsellers, which serve different functions.

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 implicitly conveys usage context: it is for a specific ASIN and provides detailed history/stats. However, it does not explicitly contrast with sibling tools or state when to choose this over keepa_search or keepa_deals. The example gives a concrete usage scenario, but explicit when/when-not guidance is missing.

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