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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description still adds substantial behavior an agent could not infer: data provenance (PNCP, published by the agencies), `total_registros` as a universe-size signal, and the failure contract that a non-`ok` `fontes[0].status` such as `limite_excedido` returns null `dados` — with retry guidance instead of concluding there are no results.

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?

Front-loads the resource and scope, then usage, then source provenance, then the explicit 'NÃO cobre' exclusion list, then the failure-handling note. Nearly every sentence carries information, though the combined body is dense enough that a small amount of trimming is possible.

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?

An output schema exists, so return-value documentation is not the description's burden, yet it still supplies the one output fact an agent must act on (null `dados` on source failure/limit). Together with source, scope, rate/looping behavior and exclusions, nothing needed to invoke this external-API tool correctly 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%, so descriptions of uf, pagina, modalidade and encerramento_ate already come from the schema (baseline 3). The description earns above baseline by explaining that modalidade is mandatory in the PNCP source itself and that scanning multiple modalities requires one call each — semantics the schema's enum listing does not convey.

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?

States a concrete resource and its exact scope (licitações still receiving proposals, filtered by modalidade and optional UF), plus the fields returned (órgão, objeto, valor estimado, prazos, edital link). Sibling differentiation is only implicit — contratacoes_do_orgao is never named — but the 'by modality/UF, not by agency' framing gives an agent enough to route correctly.

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?

Gives an explicit use case ('Use para achar oportunidades de venda ao governo') and a clear when-not block ('NÃO cobre: busca por palavra no objeto, propostas encerradas, quem venceu'). It also explains the operational pattern of calling once per modalidade. It stops short of naming the sibling tools as alternatives, so it is not a full 5.

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