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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses that it performs a live BACEN lookup by modality+month and that the average rate is only a reference, not a ceiling. This adds meaningful behavioral context not available from the annotations.

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?

Two dense sentences carry the domain, calculation method, live-data behavior, supported amortization systems, and a legal caveat. The identifying content is front-loaded, and every clause contributes value without filler.

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 an 8-parameter tool with no output schema, the description gives a useful high-level result (excedente por parcela) but omits the response shape, the optional taxa_bacen_am override semantics, and calculation assumptions. It is adequate for selecting the tool, but an agent may still need to inspect the schema or infer behavior to invoke it confidently.

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?

With 0% schema description coverage, the description must compensate for the input schema. It partially does by mentioning modality+mês, Price/SAC, and the per-installment excess, but it does not clarify the role of taxa_bacen_am relative to the live lookup, the source of the month, or the exact meaning of the required fields.

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 names a specific domain (revisional de contrato bancário), the core computation (recalcular financiamento pela taxa média BACEN), and the concrete output (excedente por parcela, Price ou SAC). This clearly distinguishes it from sibling calculation tools like calculo_fgts, calculo_aluguel, and calculo_trabalhista.

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 establishes the intended use case: reviewing bank financing contracts using the BACEN market rate and either Price or SAC amortization. It does not explicitly name alternatives or say when not to use it, but the domain and method are clear enough to guide an agent toward this tool.

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