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

With no annotations, the description carries the full burden. It usefully discloses that reference_date recomputes with the historical tax table ('refazer um mês passado com a tabela da época') and that deductions include book expenses, dependents, alimony and INSS. But it does not specify return format/units or mention how the progressive table applies to net taxable income, leaving some behavioral ambiguity.

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?

Three dense sentences in Portuguese: purpose+examples, historical behavior, and required/optional param names. No filler—each sentence earns its place, and the most distinctive information (DARF 0190, income types) is front-loaded.

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?

The description explains the calculation domain, the eligible income, the deduction items, the historical-table behavior, and the exact parameter names/requirements — a strong set for a 6-param calculator with no output schema. The only notable omission is an explicit statement of what the function returns (e.g., tax amount in R$), so it falls just short of a 5.

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 coverage is 100% and each parameter has its own description, so the baseline is 3. The description adds a meta-instruction to use the exact English parameter names and marks monthly_income as required and the rest optional, which is helpful but largely restates the schema's required array and property names.

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 opens with 'Calcula o carnê-leão do mês (DARF 0190)' — a specific verb, tax form, and period — and enumerates the exact income types it applies to ('aluguel direto do inquilino, honorários de autônomo, rendimentos do exterior'). This level of specificity distinguishes it from generic DARF and RPA calculators among the 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 clear applicability context by listing the income sources and deductible items, so an agent can choose it for monthly carnê-leão obligations. However, it never names alternatives or states when not to use it (e.g., annual IR via simulate_income_tax), so it earns 4 rather than 5.

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