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

Annotations already carry the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false), but the description adds substantial behavioral context: what 'Nada consta' actually means, that failures surface as null in `dados` rather than an empty list, that `truncado: true` signals a page cap, and that CPF records are discarded. This is exactly the value-add beyond structured fields.

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?

Content is front-loaded (purpose, then when-to-use, then caveats) and every clause carries information, though the caveat block is dense and slightly longer than needed. Structure is logical and skimmable.

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?

With an output schema present and rich annotations, the description covers the remaining gaps an agent needs: scope limits (four federal registries only, no state/municipal), the null-vs-empty distinction, truncation signaling, and the no-PF-fields constraint. Nothing material is 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?

Schema coverage is 100% for the single `cnpj` parameter and the schema already documents the masked/unmasked format and check-digit validation. The description's 'com ou sem máscara' merely echoes the schema, so baseline 3 applies with no meaningful addition.

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 first sentence names a specific resource (empresa brasileira sanctions by CNPJ) and enumerates the exact federal registries covered (CEIS, CNEP, CEPIM, leniência). It also explicitly distinguishes itself from the sibling relatorio_completo, so an agent can route correctly without opening either schema.

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?

A dedicated 'Quando usar' clause states the triggering condition (impedida, inidônea, punida pela Lei Anticorrupção, acordo de leniência) and points to the alternative (relatorio_completo) for the full view. Both when and which-alternative are explicit.

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