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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description adds value by disclosing the output scope (only same-model active listings), the max_results hard cap of 8 not present in the schema, and the effect of cheaper_only. It does not discuss response shape, but this is a minor gap for a read-only list tool.

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 description is compact and front-loaded: scope, example, trigger, exclusion, and parameter constraints each earn their place. The parenthetical packs parameter semantics without redundant 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?

For a simple 3-parameter read-only tool with rich annotations, the description is complete enough for correct selection and invocation: it identifies the input car, optional result limits and filters, and what kind of listings are returned. No critical operational details are missing.

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 takes on the parameter burden: it explains max_results default 5 and max 8, and cheaper_only=true returns only listings cheaper than the given car. car_id is only implicitly described as 'DESTE carro', which is slightly thin but recoverable from the tool's context.

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 uses a specific verb+resource: it returns other units for sale of the same model/car, illustrated with examples like cheaper options and other colors/years. It also clearly differentiates from the sibling get_alternative_models by stating it must not be used to suggest different models.

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?

It provides an explicit positive trigger ('Use para ... DESTE carro?') and a clear exclusion ('NÃO use para sugerir modelos diferentes'), so an agent knows when to invoke this tool versus an alternative-models tool. No inference is required.

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