bcb_cambio_cotacao

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

Annotations already indicate read-only, idempotent, non-destructive behavior. The description adds substantial context: default 7-day window, business-day-only availability, Refinitiv as parity source, and the literal disclaimer pass-through. No contradiction with annotations.

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?

Though long, every sentence provides necessary info: purpose, usage boundaries, return fields, defaults, and caveats. It is well-structured and front-loaded, earning its length.

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 description covers all essential context: data source, return fields, date behavior, currency symbol discovery, and explicit alternatives. With output schema present and detailed annotations, this is fully complete for an agent to select and invoke 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?

Schema covers 100% of parameters, so baseline is 3. The description adds meaningful behavioral context about the default date range and the mutually exclusive use of data vs dataInicial/dataFinal, which goes beyond the schema's field-level descriptions.

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 queries the PTAX exchange rate of a currency against the real, for a specific day or date range. It distinguishes itself from siblings by explicitly naming bcb_serie_valores and bcb_cambio_moedas, making its unique role unmistakable.

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 provides explicit 'Quando usar' and 'Quando NÃO usar' sections, naming specific alternative tools and the exact contexts for each. This is exemplary guidance for tool selection.

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