get_ptax_by_date

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

No annotations are provided, so the description carries the burden. It adds useful context like 'official closing' and 'Banco Central do Brasil', but it does not disclose edge-case behavior for non-business days, availability, or output format. This makes the description adequate but not fully transparent.

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 a single, front-loaded sentence with no wasted words. It names the provider, the rate, the asset pair, and the scope without repeating schema 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?

For a simple one-parameter read tool, the description provides enough information for source, scope, and purpose. It would benefit from stating behavior on non-business days and the expected return value, especially since no output schema is provided.

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 fully documents the single parameter with name and pattern. The description adds little beyond restating that the date is specific, so the schema remains the primary source of parameter semantics.

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 states a specific action ('Get'), a clear resource ('official closing USD/BRL PTAX exchange rate'), and a specific scope ('for a specific date'). This clearly distinguishes it from the sibling tools by_period and latest.

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 phrase 'for a specific date' implies this is the tool to use for a single-day lookup, and the sibling names indicate period/latest alternatives. However, the description does not explicitly say when to prefer this over the other tools or when to exclude them.

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