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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds important behavioral context beyond annotations: payment via prepaid credits, no credentials required, public data access, and LGPD responsibility. It does not contradict annotations, and the added details help the agent understand the operational constraints.

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 purpose, and includes relevant operational details (payment, public data, LGPD). It is concise without being overly verbose. The legal disclaimer is slightly extra but adds value for compliance. No unnecessary redundancy.

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?

Given the tool has only 2 parameters, no output schema, and simple boolean flags, the description covers the main purpose, payment model, data accessibility, and legal responsibility. The only notable gap is the undocumented 'completo' parameter. Otherwise, the description is sufficiently complete for correct invocation and understanding.

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?

The input schema has 2 parameters with 0% description coverage. The description explicitly mentions CPF as the key parameter ('a partir do CPF'), but it does not explain the meaning of the 'completo' boolean parameter. Since the schema lacks descriptions for both, the description partially compensates but leaves the 'completo' parameter ambiguous, resulting in a baseline score of 3.

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 clearly states the tool's purpose: 'Consulta o Cadastro Nacional da Agricultura Familiar (CAF) de uma pessoa física a partir do CPF.' It identifies the specific verb (consulta), resource (CAF), and input (CPF), and distinguishes it from unrelated sibling tools like 'authenticate' and 'connect'.

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 context for when to use the tool: it mentions 'sem credenciais' and 'pague por consulta com crédito pré-pago', indicating no credentials are needed and payment is required. It also notes that it queries 'informação de ACESSO PÚBLICO', clarifying it is appropriate for public data. While it does not explicitly name alternatives, the sibling tools are unrelated, so the usage context is sufficient.

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