Simula o Tesouro Selic com a Selic de hoje (Banco Central): rendimento composto, IR regressivo e a taxa de custódia da B3 de 0,20% ao ano, com a isenção sobre os primeiros R$ 10 mil. Parâmetros obrigatórios: principal, months. Use exatamente estes nomes, em inglês.
| Name | Required | Description | Default |
|---|---|---|---|
| months | Yes | Prazo em meses (1-360) | |
| principal | Yes | Valor investido em R$ |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It does this well by revealing key modeling assumptions: current Selic from Banco Central, compound returns, regressive income tax, B3 fee of 0.20% p.a., and the R$10k exemption. It does not describe output format or limitations, but the core behavior of the simulation 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 one dense but well-organized sentence that front-loads the purpose and then packs the key modeling details. The parameter-name instruction is clear and useful, though the sentence is slightly long and could be split for readability.
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 two-parameter calculator with no output schema, the description supplies the important assumptions an agent needs to invoke it correctly. It omits any description of the return value, but that is not critical when no output schema exists and the tool's purpose is straightforward.
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%, so the schema already documents both parameters with descriptions and constraints. The description reinforces that principal and months are mandatory and insists on exact English names, but it adds no new semantic meaning 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 starts with a specific verb ('Simula') and a precise resource ('Tesouro Selic'), then names the exact calculation components: current Selic rate, compound yield, regressive IR, B3 custody fee, and the R$10k exemption. This clearly distinguishes it from siblings like calculate_tesouro_prefixado and calculate_cdi_yield.
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 usage context is implied: it should be used when the user wants a Tesouro Selic simulation under current Selic conditions. However, it does not explicitly state when to prefer this tool over the many sibling calculators, nor does it mention exclusions or alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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