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

Annotations already declare read-only and non-destructive, so the safety profile is covered. The description adds that values are 'atualizados' and 'valores vigentes', clarifying data is current, but it doesn't describe the return format or update frequency, leaving some behavioral gaps.

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 moderately long but front-loaded with the main action, followed by usage guidance and English keywords. The English keyword section adds length but serves multilingual matching, so it earns its place.

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 no-parameter, read-only tool with no output schema, the description covers purpose, usage, and scope well. It lists exact indicators and differentiates from siblings, though it stops short of describing the response structure, which would improve completeness.

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 has no parameters and an empty schema, so there is nothing for the description to explain. Per the evaluation baseline for zero parameters, this scores 4.

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 it returns current Brazilian financial indicators (Selic, CDI/DI, IPCA, poupança) with a specific verb and resource. It distinguishes from get_future_projections by explicitly addressing expectations/future curve, avoiding confusion with siblings.

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?

It provides explicit usage scenarios: when users ask about current rates, economic indicators, inflation, interest rates, or fixed-income benchmarks. It also directs users to get_future_projections for market expectations or future curves, giving a clear alternative.

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