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

Adds real behavior beyond the annotations: it discloses latency per source (Mercari ~20s, AU/FR ~30s) and explains that it 'uses one read and saves the result in the user's Puley history', which accounts for readOnlyHint=false. It also notes seller names are omitted from results. It does not discuss failure modes or rate limits, so not a 5.

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?

The long parenthetical country list is dense and front-loaded with marketplace names before the actual usage rules, which buries the key place-format guidance mid-sentence. Most of the content earns its place, but the structure could be tightened into clearer clauses.

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 4-parameter, no-output-schema tool, the description covers inputs, per-source latency, and the shape of returned ads (title, price, place, posted time, description, photo, link, no seller names). That is nearly complete; only error/empty-result behavior is unaddressed.

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?

With 0% schema description coverage, the description carries the full burden and largely does: it defines place formats per country, the country code set and default, max_price currency semantics and the 0 sentinel, and a query-language tip. Only 'query' itself gets no elaboration beyond the Japanese note.

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 ('Second-hand and local ads') and enumerates the exact marketplaces covered, so an agent knows precisely what corpus is searched. It does not explicitly differentiate itself from close siblings such as search_marketplace, find_ads, or resale_prices, which keeps it from a 5.

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?

Gives concrete usage context: country defaults to ZA, place accepts a town/province/postcode or a ZIP or 'city, state', max_price is in local currency with 0 meaning any, and Japanese queries work best for Mercari. It stops short of saying when to prefer this over sibling ad/marketplace tools or when not to use it.

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