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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well covered. The description adds behavioral context: it reveals the tool performs a calculation (no side effects), returns monthly breakdown plus total, and applies a legal formula. It also says it corrects overdue months to the current date, which is non-obvious. This exceeds baseline given annotation coverage.

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 sentences with high information density. It front-loads the legal basis and outcome, then lists the exact variables and return value. No filler or redundancy.

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 9-parameter calculator with no output schema and 0% schema coverage, the description conveys the core algorithm and output shape. However, it does not explain how optional params (juros, multa, indice, periodicidade_meses, data_calculo) alter the calculation when omitted, and it doesn't mention whether indices rates are fetched internally or must be supplied. The main purpose is clear, but edge cases around optional parameters are not fully covered.

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 carries the burden for parameters, but it only names general concepts: aluguel_inicial, inicio_contrato, inicio_atraso, fim_atraso, juros, multa, indice. It does not specify formats (ISO dates?), how optional params behave, or which combination of fields is required. The required fields are obvious from names, but the semantics of juros/multa/indice/periodicidade_meses could benefit from more explicit definitions.

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 a specific verb 'calcula/reajusta' with a specific resource (aluguéis em atraso) and cites the legal basis (Lei 8.245/91). It lists the applicable adjustments (índice, juros de mora, multa moratória) and what it returns (detalhamento por mês + total). This distinguishes it from sibling calculation tools.

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 implies usage for overdue rent calculations under Lei 8.245/91, and the detail about applying index adjustments, late fees, and interest makes it clear. It does not explicitly tell when not to use it or point to alternatives like calculo_atualizar or calculo_indice, but the context is sufficiently clear for a domain-specific calculation tool.

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