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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses page size (~27), the hard page cap (1-20), that a total listing count is included, that data comes via a residential proxy, and the exact billing model ($0.002 USDC per successful call, failed calls not charged). That pricing and failure-behavior disclosure is exactly the kind of context an agent needs before calling a paid endpoint.

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?

Front-loaded with the resource and returned fields, then pagination, then pricing — the ordering is good and nothing is redundant. It is a single long run-on sentence, which makes it slightly dense to scan, but every clause carries information.

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 description needn't detail return formatting, and it still covers scope, pagination limits, source, proxy, and cost. For a three-parameter paid scraper tool, an agent has everything needed to decide and call 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%, so the parameters are already documented; the description still adds value by tying page to the 1-20 limit and giving results-per-page context that the schema lacks. It does not, however, explain province/city coupling or case/format expectations beyond the schema examples.

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 ('Zoocasa (Canada) homes for sale in a city') and enumerates the exact fields returned, so an agent knows precisely what data comes back. The named source (zoocasa.com) distinguishes it from sibling Canadian listing tools such as realestate_realtor_ca.

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?

Usage is implied by the source and scope (Canadian city listings, page 1-20), but there is no explicit when-to-use statement, no exclusion of alternatives, and no mention of how it differs from other Canada-focused real estate siblings. Adequate but leaves routing to inference.

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