ipca_periodo

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

Since there are no annotations, the description carries the responsibility. It clearly states the output ('Retorna variação percentual mensal') and implies a read-only operation. It lacks details on error conditions or data availability limits, but for a simple query tool this is sufficient.

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 concise, using only two sentences. It front-loads the primary purpose and includes the key output detail, with no extraneous 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?

The tool is simple and has an output schema, so the description does not need to explain return values. It provides enough context (useful for inflation and monetary correction) and specifies the data source and series, making it complete for an agent to decide when to invoke it.

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 schema already provides full descriptions for both parameters (data_inicio and data_fim) with format and default values, achieving 100% coverage. The description adds no additional semantic information beyond what the schema already states.

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 clearly states the tool consults the IPCA accumulated monthly index from the Central Bank of Brazil (BCB/SGS series 433), with a specific verb ('Consulta') and resource ('IPCA'). It distinguishes itself from sibling financial tools like taxa_selic or ptax_data by naming the exact inflation index.

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?

The description provides a general use case ('Útil para cálculos de inflação e correção monetária') but does not explicitly compare with alternatives such as calcular_correcao_monetaria or taxa_selic. The guidance is implied rather than explicit.

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