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

Annotations already declare readOnly/idempotent/openWorld, but the description adds substantive data caveats the annotations cannot: the PNCP source, filtering by publication date, and detailed LGPD behavior (physically-owned-supplier contracts omitted, counted in `omitidos_pessoa_fisica`, name masked with a `fornecedor_nome_omitido_lgpd` flag). These materially change how an agent should interpret 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?

Purpose is front-loaded and the 'NÃO cobre' and LGPD clauses are clearly marked, so the density is justified. The LGPD sentence is long and slightly run-on, but every clause carries distinct, actionable information.

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 read-only, output-schema-backed tool, the description covers purpose, source, coverage limits, and the LGPD caveats that a caller must know to interpret `omitidos_pessoa_fisica` and `fornecedor_nome_omitido_lgpd`. Nothing needed to invoke or read the result sensibly 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 the baseline is a 3, but the description adds real meaning by clarifying that the date range filters on publication date (not signature date), which the schema's date parameter docs do not state. The 366-day window is only in the schema, so it adds nothing there.

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 verb and resource (contracts published by a public agency) and enumerates the returned fields (supplier CNPJ, object, values, signature, validity). Its scope is clear, but it does not explicitly distinguish itself from the sibling contratacoes_do_orgao (procurements vs. signed contracts), so sibling differentiation is left implicit.

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?

Explicitly gives the when ('Use para ver quem o órgão contrata e por quanto') and the when-not ('NÃO cobre: contratos fora do PNCP, nem busca por fornecedor'), routing the supplier-identification case to another source. This is exactly the kind of exclusion and alternative guidance an agent needs.

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