compras_indicadores_por_periodo

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

Annotations already establish read-only, idempotent, non-destructive behavior; the description adds operational context beyond those signals: it identifies this as a Dados Abertos endpoint and discloses a 1-hour cache freshness window. This gives the agent important stale-data awareness without contradicting any annotation.

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 is compact and front-loaded: purpose, endpoint, return semantics, negative scope, use case, and cache behavior each get one focused sentence or clause. No filler or redundant elaboration.

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 a fully documented schema, a present output schema, and safety annotations, the description supplies the remaining operational context: endpoint identity, data semantics, non-purchase scope, intended temporal analysis, and cache behavior. An agent has everything needed to call and interpret the tool correctly.

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?

The input schema covers 100% of parameters with complete descriptions, so the description need not repeat them. It adds only the high-level grouping 'por período (ano/mês)' that maps to ano/mes, which is marginal extra value over the schema.

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-object pair ('Métricas operacionais da API por período') and immediately scopes the resource to API usage metrics (requisições, latência, downloads), adding a clear negative ('não dados de compras') that differentiates it from procurement-data tools. The underlying endpoint is named, leaving no ambiguity about what is being invoked.

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 gives a clear use case ('Útil para análise temporal de disponibilidade do upstream') and an explicit exclusion ('não dados de compras'). It does not name alternative sibling tools or state exactly when to prefer them, so it stops short of full when/when-not coverage.

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