bcb_cambio

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

With no annotations, the description carries the full burden of behavioral disclosure. It states the tool returns quotes for the last N business days and mentions the default of 7. However, it does not disclose error behavior, rate limits, or anything about the return format beyond what an output schema would cover. The description is honest but not deeply detailed about potential side effects or edge cases, though none are expected for a read-only query.

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 and front-loaded with the purpose, followed by parameter explanations. Each sentence earns its place, and the structure (statement then Args) is clean. Slightly under-structured with a plain paragraph, but effective and without fluff.

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 tool has an output schema (so return format is documented elsewhere), two optional parameters with defaults, and a pointer to a related tool, the description covers what an agent needs to invoke it correctly. It lacks explicit error handling or examples, but these are less critical given the simplicity and the schema.

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 0%, so the description must compensate. It explains both parameters: 'moeda' gives symbol examples (USD, EUR, GBP) and refers to bcb_moedas for the full list, and 'dias' clarifies it is the number of business days of quotes with a default of 7. This adds meaningful semantic detail beyond the bare 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 returns Central Bank PTAX exchange rate quotes for a currency over the last N business days. It identifies a specific resource (exchange rates) and action (retrieving quotes). It does not explicitly differentiate from sibling tools like bcb_serie or bcb_focus, but the purpose is unambiguous and distinct enough given the 'PTAX' specificity.

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 contextual guidance by pointing to bcb_moedas for listing available currencies, which is helpful for parameter selection. However, it does not explain when to prefer this tool over other BCB or IBGE tools, nor does it state any exclusions. Usage context is implied but not fully explicit.

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