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

With no annotations provided, the description carries the full behavioral burden and does substantial work: it discloses tax rates, the sales exemption threshold, IRRF offset, and loss compensation by modality. It does not mention output format or edge cases, but the key computational behavior is 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 description is two sentences with no fluff. The core calculation is front-loaded, and the compact parameter enumeration plus the explicit 'use exactly these names' instruction 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?

The description sufficiently covers the calculation domain, tax rules, and all 8 optional input names for a tool with no output schema. The main gap is that it does not describe what the return value looks like, but the tool's purpose makes the output largely self-evident.

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 100%, so the baseline is 3; the schema already documents each parameter's meaning. The description adds value by listing all parameter names and insisting they be used exactly in English, but it does not add deeper semantic details beyond the schema.

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 verb ('Calcula') and a precise resource: the monthly DARF of variable income for individuals. It further disambiguates by enumerating the exact modalities (swing trade, day-trade, FIIs) and their respective rates, making it clearly distinct from generic sibling calculators.

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 gives clear context on when to use the tool: for monthly variable-income DARF calculation with specific rules such as the R$ 20k exemption and IRRF compensation. However, it does not explicitly state when not to use it or point to an alternative, so it falls just short of a 5.

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