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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds a concrete behavioral fact, 'Cache 1h', which helps an agent reason about data freshness. Given the rich annotation coverage, this extra context justifies a 4.

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?

Three short sentences front-load the core behavior, then add the endpoint, intended use case, and cache behavior. There is no filler, and nothing redundantly restates the schema or annotations.

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 listing tool, the description covers what it does, the monitoring scenario, the relevant endpoint, and cache freshness. The complete schema coverage, rich annotations, and output schema cover the remaining invocation details.

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 100%, so the input schema already documents all parameters, formats, defaults, and the ~30-day window. The description adds no parameter-specific meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 opens with a specific verb+resource: 'Lista PCAs atualizados num período' and reinforces this with the endpoint and the monitoring use case. This clearly distinguishes it from sibling PCA tools like compras_pncp_pca_listar, which focus on listing PCAs rather than recently updated ones.

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?

It explicitly states when the tool is useful: 'Útil para monitoramento: descobrir quais órgãos revisaram seu PCA recentemente.' It gives clear usage context but does not name alternative tools or exclusion conditions, so it stops short of a 5.

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