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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint=false. The description adds meaningful context beyond that: 'Consulta informação de ACESSO PÚBLICO em bases e fontes oficiais', 'sem credenciais', and LGPD responsibilities. This clarifies data origin and legal framing, complementing the annotations without contradiction.

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 consists of three sentences, each adding value: purpose, payment/access, and data/legal nature. It is front-loaded with the primary purpose and avoids fluff, though it includes extras like 'Hospedado pela plataforma' that are not strictly necessary. Overall, it is concise for the information conveyed.

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 two-parameter tool with no output schema and safety annotations, the description covers essential aspects: purpose, data source, payment, and legal responsibility. However, it omits semantics of the 'completo' parameter and any guidance on output or error handling. This is a moderate gap given the tool's compliance context, but acceptable for a simple lookup.

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 must carry the burden. It explains the essential CPF parameter via 'a partir do CPF', but the optional boolean 'completo' is not explained at all. This leaves the parameter ambiguous, and the description only partially compensates for missing schema descriptions.

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: 'Verifica se uma pessoa é Politicamente Exposta (PEP) a partir do CPF' – a specific verb (verifica) and resource (CPF) with the domain context of compliance/AML. It distinguishes itself from unrelated sibling tools (system utilities) by naming the unique PEP-checking capability.

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 for when to use the tool: 'para diligência de compliance e AML' (for compliance and AML due diligence). It also mentions payment model and public data access, giving operational context. However, it does not explicitly name alternatives or exclusion cases, though siblings are not alternatives.

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