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

Annotations already declare readOnlyHint, openWorldHint and idempotentHint, so the safety profile is covered. The description adds value on top: return shape ('compact rows with price, specs, city and a link'), the fact that listing text is Polish, and that currency is PLN. It stops short of discussing pagination or result limits beyond what the schema's cursor field implies.

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?

Four compact sentences, front-loaded with the core action and domain, then segment semantics, then return shape, then currency. Nothing is padded, though the price/currency sentence slightly overlaps what the schema already says.

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 20 optional parameters and no output schema, the description carries a fair load: it explains the segment switch, the currency and language environment, and the shape of returned rows. The main gap is that it never routes the agent away from the sibling marketplace/wanted-ad search tools, which matters given the crowded search family.

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%, so the baseline is 3. The description still contributes beyond the schema by clarifying that prices are PLN and that priceMin/priceMax filter the daily/per-period rental rate for rentals, plus the Polish-language constraint on free-text and city matching. These are meaningful additions, though the schema already covers most parameter intent.

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 with domain anchoring: 'Search active camper listings on VanAuto (vanauto.pl)'. An agent knows exactly what is searched and where. It does not, however, distinguish itself from the sibling search_marketplace_listings or search_wanted_ads, so it falls short of 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?

The description gives real guidance on the segment values ('sale' for campers for sale, 'rental' for rentals) and notes the rental-specific price semantics, which is useful. But it offers no when-to-use-this-tool versus sibling search tools, no prerequisites, and no exclusions — usage is implied rather than stated.

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