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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds meaningful behavior context: no credentials needed, pay-per-query, public data only (not private/sigiloso), and LGPD compliance. This goes beyond annotations without contradicting them.

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 three sentences, front-loaded with the core purpose, then adding essential context (payment, credentials, data sensitivity). No redundant information, though it could slightly trim the LGPD detail without losing value.

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?

The tool has a simple input (1 required, 1 optional) and no output schema. The description mentions 'consulta informação' but does not specify what the response contains (fields, structure, success/error patterns). Given no output schema, some return-value detail would improve completeness.

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 0%, so the description carries the burden. It only explains 'NumeroCAR' as the input ('a partir do número do CAR') but completely omits the optional 'completo' boolean parameter. Agents cannot infer what 'completo' controls.

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+resource+scope: 'Consulta o Cadastro Ambiental Rural (CAR) de um imóvel a partir do número do CAR.' This clearly states the tool queries the CAR by its number, distinguishing it from sibling tools like authenticate or report_bug.

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 provides clear context on when to use this tool: hosted on the platform, no credentials required, payment per query with prepaid credit, and access to public official data. It does not explicitly name alternatives or exclusions, but siblings are unrelated and the context is unambiguous.

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