ptax_data

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

No annotations are provided, so the description carries the full burden. It mentions the business-day constraint but does not disclose any other behavioral aspects like authentication, rate limits, or return format. More detail would be expected.

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 very concise with only two sentences. The first defines the action and resource, the second adds a critical constraint. No wasted words.

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 low complexity (2 parameters, 1 required, output schema exists), the description adequately covers purpose and usage constraints. It could mention output structure but output schema already exists to handle that.

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% with clear parameter descriptions ('data' format YYYY-MM-DD and moeda defaults to USD). The description adds context about PTAX being compra e venda but does not significantly enhance parameter understanding beyond 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 clearly states the tool queries the official PTAX exchange rate from Brazil's Central Bank, specifying both buying and selling rates for a given date and currency. It is distinct from sibling tools like 'consultar_cep' or 'taxa_selic'.

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 key usage constraint: 'Só disponível para dias úteis' (only available for business days). While it doesn't explicitly compare with alternatives, the tool's specific function makes its context clear.

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