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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: prices are Avahit's own observations, freshness is tracked via last-verified timestamps, and Amazon prices carry a hard 24-hour retention limit due to licensing. It does not say whether Amazon ids error out or return empty.

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 core action and the identifier requirement before enumerating the returned fields. The field enumeration is dense but each item is distinct information an agent could use; the Amazon caveat is correctly placed last as an exception note.

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 usefully enumerates the returned fields and explains the one major data gap (Amazon history), which is exactly the kind of thing an agent needs. Remaining omissions — error behavior for unknown or Amazon ids, and whether results are paginated — are minor for a single-parameter read 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% for the single productId parameter, so the description must carry the load. It does add meaning by specifying the id is an 'Avahit product id' (distinguishing it from an Amazon identifier), but it gives no format, length, or validation guidance beyond 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 gives a specific verb (return) and a precisely scoped resource: what Avahit itself observed about a product's price, enumerated as current price, verification date, low/high with dates, average, and check count. It implicitly separates itself from get_store_sales by emphasizing Avahit-observed rather than store-reported data, but it never names or contrasts a sibling explicitly.

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 phrase 'Given an Avahit product id' plus the Amazon caveat, which tells the agent this tool is useless for Amazon products. However, there is no explicit when-to-use statement and no routing to alternatives such as get_store_sales or compare_alternatives.

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