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

With no annotations, the description carries the full burden of behavioral disclosure. It explains the calculation mechanics in detail: IPCA is applied multiplicatively, the legal rate is additive, interest is simple and applied to the already-updated value, and it returns the complete calculation memory. This goes well beyond a generic 'update value' statement.

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 dense but every sentence carries essential information: legal basis, calculation method, scope exclusions, return value, and parameter naming requirements. The front-loaded action and legal framing allow quick understanding, with details and warnings following in a logical sequence.

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?

Given the moderate complexity and absence of an output schema, the description covers the required parameters, calculation order, legal references, and exclusions, and it states the return value ('memória de cálculo completa'). It does not specify rounding or formatting details, but for this tool the information provided is sufficient for correct invocation.

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 baseline is 3, but the description adds value by explicitly listing the required parameters, insisting on exact English names, and reinforcing the multiplicative vs. additive roles of the two rate parameters. This helps an agent map the parameters to the Formula described.

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 states the specific action ('Atualiza um valor') and the precise legal regime (Lei 14.905/2024, CC arts. 389 and 406), making it clear this is a civil monetary update calculator. It distinguishes itself from sibling calculators by specifying the civil regime and explicitly excluding labor, tax, and public treasury debts.

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: use for civil regime updates under the named law and effective date. It also provides an explicit when-not ('não presume aplicação a débitos trabalhistas, tributários ou contra a Fazenda Pública'), though it does not name alternative tools for those cases.

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