Calcular parcelas (Price)

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

With no annotations, the description carries the full burden and does meaningful work: it declares the amortization system (Price), the compounding model (juros compostos), and explicitly enumerates what is excluded from the result (IOF, fees, insurance). It does not disclose rounding behavior, which matters for a financial calculation.

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 short sentences with zero filler; the computation method is front-loaded and the unit clarification and exclusions follow in order of importance. Nothing is redundant.

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 pure computation tool with 3 required numeric params, full schema coverage and an output schema, the definition covers method, rate unit and result scope. The only meaningful gaps are rounding/precision conventions and the absence of any annotations, which the description partly offsets.

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 all three parameters are already documented, establishing a baseline of 3. The example '1.99' usefully reinforces that the rate is a percentage (not a decimal fraction), but that repeats what the schema already says ('Taxa de juros em % ao mês').

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?

States a specific verb and resource ('Calcula parcelas fixas') and names the exact method used ('tabela Price com juros compostos'), which is the key disambiguator versus other amortization systems. An agent can tell precisely what computation this tool performs without consulting 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 description scopes the result ('Não inclui IOF, tarifas nem seguros'), which implicitly tells the agent when the output is or isn't sufficient, and clarifies the rate unit. However, it never states when to prefer this tool over alternatives or what preconditions apply (e.g. rate must be non-negative, max 1200 installments).

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