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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description does not need to re-establish safety. It adds useful behavioral context: the BACEN/IBGE date inclusion convention, the conditional outputs depending on `valor` and `incluir_valores`, and the fact that enabling `incluir_valores` pulls raw monthly index values. This goes beyond what the annotations and schema alone convey.

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 compact and front-loaded with the resource and the core calculation outcome. The two sentences each carry distinct information: the main calculation convention and the conditional output behaviors. The informal phrase 'puxar os índices crus' is slightly loose but does not substantially hurt clarity or structure.

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 there is no output schema and six parameters, the description covers the essential calculation semantics, date convention, and optional outputs. Still, the unexplained `pro_rata` parameter and the lack of any detail on the return format or error conditions leave notable gaps. It is adequate for a straightforward read-only index lookup but not fully complete for all six parameters.

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 0%, so the description must compensate. It adds semantics for `data_inicial`/`data_final` via the date convention, for `valor` via the corrected-value behavior, and for `incluir_valores` via monthly variations. However, it does not explain `pro_rata` and gives almost no explicit guidance on the `indice` parameter beyond the fact that it is an official index, leaving a meaningful gap for a 6-parameter tool.

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 clearly identifies the tool's function: querying an official index and returning an accumulated correction factor between two dates. It also specifies key conventions (month start excluded, month end included) and optional behaviors (corrected value, monthly variations). It does not explicitly differentiate from sibling tools, though 'índice oficial' and the calculation semantics make the resource distinct.

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 implies when to use the tool based on parameters: if `valor` is provided it returns the corrected amount, and if `incluir_valores` is true it returns published monthly variations. However, it does not explicitly state when to choose this tool over sibling tools such as `calculo_aluguel` or `calculo_atualizar`, nor does it mention any prerequisites or exclusions.

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