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

Annotations already mark this as read-only, idempotent, open-world, and non-destructive, and the description does not contradict them. It adds valuable behavioral context beyond the annotations: the result includes lowest/median/highest price, offer count, freshness, and best matched listing, that it rejects likely identity mismatches, and that it costs 0.01 USDC via x402.

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 sentences, each earning its place: purpose/scope, return summary and cost, then usage timing. The most important information is front-loaded, and there is no repetitive or filler wording.

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 tool with an output schema and read-only annotations, the description is largely complete: it states prerequisite, cost, data sources, and the shape of the returned intelligence. It could be more complete by naming sibling alternatives or giving explicit when-not-to-use conditions, but these gaps are minor.

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?

The schema already documents query and id, and the anyOf structure conveys that one of them is required, while lang has an enum/default. The description does not add any parameter-level guidance beyond saying the item is 'identified', so it provides no additional semantic value for choosing or formatting parameters.

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 opens with a specific verb and resource: 'Get current matched asking-price intelligence for an identified Japanese anime collectible', and names data sources (Yahoo Shopping, eBay, stored market observations). It also differentiates itself from identify/search siblings by restricting use to an already identified item and by enumerating the price summary outputs. This is unambiguous and not a tautology.

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?

It explicitly states when to use the tool: 'Use after identity is known' and when the user asks for current price, market range, cheapest observed listing, or current availability. It does not explicitly name alternative sibling tools or give 'when not to use' exclusions, so it stops short of a 5.

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