bcb_cambio_moedas

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds value by disclosing that the response repasses the BCB disclaimer literally, that exchange rates only exist on business days with currency closing, and the data source. No contradictions 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?

The description is well-structured with clear sections: function, when to use, when not to use, return fields, source, and caveat. Every sentence contributes useful information, and the most important usage guidance is front-loaded.

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?

Given the simple one-parameter tool, the strong annotation set, and the output schema presence, the description is complete: it explains purpose, usage boundaries, return fields, source, disclaimer behavior, and business-day limitation. No significant context 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?

The input schema already provides full coverage for the single optional param 'termo', including examples. The description repeats that the tool 'aceita um termo para filtrar' but adds no new syntax or interpretation beyond the schema, so the baseline of 3 applies.

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 and resource: 'Lista as moedas com cotação publicada pelo Banco Central, com símbolo, nome e tipo', and notes the optional filter. It clearly distinguishes the tool from sibling bcb_cambio_cotacao by stating it is for discovering symbols, not for retrieving exchange rate values.

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 gives explicit when-to-use guidance ('para descobrir o símbolo correto antes de chamar bcb_cambio_cotacao') and when-not-to-use guidance ('para valores de cotação'), naming the relevant sibling tool and explaining the common failure mode it prevents.

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