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

Goes well beyond the readOnlyHint/openWorldHint annotations by disclosing the billing model: $0.002 USDC per successful call via x402 on Base, Solana or Arc, with failed calls not charged. That is exactly the kind of cost/auth context annotations cannot express; only pagination/sort behaviour is left unstated.

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 sentences, front-loaded with the resource and scope before the commercial terms. The long enumeration of returned fields is somewhat wasted since an output schema already exists, but the text is dense and free of filler.

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 an output schema present, the return-field list is arguably redundant rather than necessary, and the annotations cover the read-only/open-world profile, so the remaining gap is small: nothing is said about how limit interacts with the returned total or about result ordering. Otherwise an agent has enough to call it correctly.

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 100% and there are zero formal enums, so the description's 'buy or rent' and 'flat, house, parking or land' phrasing supplies the effective allowed values for deal and type. It still says nothing about limit or maxPrice semantics, so it adds value but not across the whole parameter set.

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 resource (French property ads from Bien'ici) with scope (city or area) and enumerates the attributes returned, so an agent can distinguish it from other real-estate portals such as rightmove, zoopla or even the other French source, seloger, without opening the schema.

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?

'To buy or to rent; flats, houses, parking or land' signals the supported query modes, but there is no explicit when-to-use guidance, no mention of when a different portal tool would be preferable, and no prerequisites stated. Usage is implied rather than directed.

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