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

With no annotations, the description carries the burden of behavioral disclosure. It clearly identifies this as a data-retrieval snapshot from the Central Bank of Brazil and discloses the $0.01 cost, which are important traits. It does not describe freshness, response format, or failure behavior, but for a zero-parameter read-only snapshot this is reasonably 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 definition is a single compact sentence, front-loads the core value proposition, enumerates the included data, and adds pricing without unnecessary detail. Every clause contributes useful selection 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?

Given the zero-parameter schema and no output schema, the description provides enough context for an agent to understand what data comes back: official PTAX rates, Selic, CDI, IPCA, and business-day status. It could be more complete by specifying response structure or data freshness, but the essential information is present.

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 tool takes zero parameters, so there are no parameter semantics to explain. The description correctly presents the tool as a no-argument snapshot, and the baseline for zero parameters 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 clearly identifies a Brazil macro snapshot and enumerates the exact data included: PTAX USD/BRL and EUR/BRL, Selic, CDI, IPCA, and business-day status. It implies aggregation versus the individual sibling tools like get_ptax, get_rates, and business_days, but does not explicitly name or differentiate them.

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 'Brazil in one call' implies the intended use case: retrieve multiple Brazil indicators together instead of calling individual endpoint tools. However, it does not explicitly state when to use this versus get_ptax, get_rates, or business_days, nor does it provide exclusions or prerequisites.

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