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

With no annotations, the description carries the full burden and does add real behavioral context: it discloses the exact return shape (score, ratios, counts across time windows) and the cost model ('Flat 5 points per successful run'). The cost disclosure especially is behavioral information that structured fields do not provide. It stops short of stating read-only status or rate limits.

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 tightly packed sentences that lead with the returned data and end with the cost, so nothing is wasted. The first sentence is a dense enumeration but remains readable and front-loaded.

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 single-parameter read-only aggregation with no output schema, the description fully explains what the return contains, which is exactly what's needed. The only omission is guidance on selecting it over the review-list sibling, which is 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?

Schema description coverage is 100% and the single 'seller' parameter is well documented in the schema with an example ID/URL, so the description need not compensate. It adds no extra meaning about the parameter, making the baseline 3 appropriate.

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 states a specific verb and resource: it aggregates a Yahoo! Auctions Japan seller's feedback score, enumerating exactly which metrics (total/positive percentage as seller/buyer plus positive/neutral/negative counts across five windows). The 'Aggregated' framing implicitly distinguishes it from the sibling run_yahoo_auctions_sellers_reviews that lists individual reviews, though it does not name 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?

There is no explicit when-to-use, when-not, or named alternative, so usage is only implied by the aggregation scope. An agent can infer this is for summary stats rather than individual reviews, but the description never says so directly.

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