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

Annotations already declare the read-only, idempotent, non-destructive, closed-world safety profile, so the description is not required to carry that burden. It adds genuine behavioral context: the tool is query-anchored with no enumerate-the-archive mode, and it discloses the shape of the returned evidence. It does not mention the plan cap on results or pagination behavior.

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 that are front-loaded with the core purpose, followed by the usage condition and the query-anchored constraint. No filler, though the second and third sentences are somewhat terse fragments rather than fully integrated guidance.

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?

For a read-only query tool whose annotations already cover the safety profile and with no output schema, the description is nearly complete: it explains what evidence is returned, the query-anchored nature, and when to prefer it. Only the result cap and the exact alternative tool are left unstated.

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 coverage is 60%, so the schema documents most parameters itself. The description reinforces the required q parameter ('describe an item') and mentions state among returned fields, but adds no syntax or format detail for limit, country, or category beyond what the schema provides. Baseline 3 is appropriate at this coverage level.

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-resource pair (retrieve individual archived sales behind an item) and enumerates the returned fields (title, final price, sale month and state, plus the resulting range). It contrasts with an unnamed sibling via 'the evidence rather than just the number,' which implicitly distinguishes it from aggregate tools like get_sold_comps, but never names that sibling.

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?

'Use when you want the evidence rather than just the number' gives a clear scenario, and 'Query-anchored — describe an item; there is no way to list the archive' states a hard usage constraint. It stops short of naming which sibling to use for the aggregate number, leaving that comparison to inference.

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