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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description does not contradict them. It adds genuine behavioral context beyond the annotations: the exact data payload shape and the 24-hour retention limit driven by Amazon's licence, which explains why Amazon results are empty rather than erroring.

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?

Two sentences, front-loaded with the purpose and the enumeration of returned fields, with the Amazon caveat placed last where it does not interrupt the primary instruction. Every clause carries information; nothing is redundant with the name or schema.

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 effectively serves as the return contract by listing current price, verification date, low/high with dates, average, check count, and tracking start. The Amazon limitation closes the main expected edge case for a read-only tool.

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 0%, so the description carries the burden, and it does constrain the parameter by stating it must be an 'Avahit product id' — implying an Amazon ASIN will not work. It does not give the id format or an example, leaving a small gap for a single required string parameter.

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 ('return what Avahit itself observed about its price') and enumerates the exact fields returned, which no sibling does. The scoping phrase 'what Avahit itself observed' implicitly separates it from store-side or comparative data offered by siblings like get_store_sales or compare_alternatives.

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 a clear usage boundary: Amazon products have no history because of a licensing constraint, so the agent knows not to expect results for them. It does not name an alternative tool for the Amazon case or state prerequisites explicitly, but the applicability condition is unambiguous.

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