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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behavior, so the bar is lower. The description adds behavioral context by explaining the two output-producing search paths and framing the tool as the fastest route to a fipeId; nothing contradicts the annotations.

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, no filler, with the main purpose and fastest path front-loaded before parameter combinations. Every clause earns its place.

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 read-only lookup with three optional parameters and no output schema, the description covers both search modes and the intended result. It does not spell out the exact response fields or the no-argument edge case, but the annotations plus the usage modes are enough for an agent 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%, so the baseline is 3; the description goes beyond it by explaining how the parameters combine (`termo` can be restricted by `marca`, while `marca`+`modelo` is the exact slug shortcut) and by giving concrete examples like 'corolla xei' and 'onix ltz'.

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 opens with a specific verb and resource ('Acha versões de veículo no catálogo Carpedia') and states the intended outcome ('chegar num fipeId'). This clearly differentiates it from sibling brand/model search tools.

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 explicitly presents two invocation modes: free `termo` search with optional `marca` restriction, or exact `marca`+`modelo` slugs to list versions. The guidance is clear for choosing parameters, though it does not name sibling tools or state when not to use this tool.

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