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

With no annotations, the description carries full responsibility, and it discloses substantive behavior: R$ 35k exemption for Brazil custody, progressive rates above it, DARF 4600, and the Lei 14.754 15% annual-adjustment regime with no exemption for foreign-held crypto.

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 front-loaded with the primary verb and object, then compacts the key rules into a colon-delimited list and three short parameter sentences. No filler or repeated schema content.

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 complex tax calculator with no annotations and no output schema, the description supplies the regimes, threshold, and parameter mapping needed to invoke it. The only notable gap is that it never states the return contract explicitly (e.g., computed DARF amount or tax value), so the agent must infer the output.

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 schema already covers all three parameters at 100%, so the baseline is 3; the description adds a useful guard by naming required and optional parameters and insisting on exact English names ('Use exatamente estes nomes, em inglês'). It does not add new semantic detail beyond the schema, hence not a 5.

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 the exact operation ('Calcula o imposto sobre ganhos com cripto') and scopes it with three tax regimes, so an agent can distinguish it from generic tools like calculate_darf or calculate_imposto_apostas without opening the schema.

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 opening clause gives clear selection context: use for crypto capital-gains tax, with monthly-sales threshold and foreign-exchange special regime. It does not explicitly name sibling alternatives or state when not to use it, so it misses the top score.

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