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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral detail beyond that, such as the BACEN/IBGE date convention and the two output modes depending on `valor` and `incluir_valores`. There is no contradiction with the annotations.

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 well-structured: the first sentence states the core purpose and date convention, and the second covers the two conditional behaviors. Every clause adds information, with no redundant filler.

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 no output schema, 0% schema description coverage, and six parameters, the description is incomplete. It fails to explain the `pro_rata` behavior, the expected date format, what happens when `data_final` is omitted, or the shape of the returned data. An agent would likely need additional trial and error to invoke this correctly in all intended cases.

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, but it only explains `valor` and `incluir_valores` explicitly. The `pro_rata` parameter is not mentioned, and `indice`, `data_inicial`, and `data_final` lack detailed semantics beyond the general 'entre duas datas' context. This leaves significant ambiguity for a six-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 a specific action ('Consulta de índice oficial') and resource: the official index correction factor between two dates. It also adds a precise month convention (initial month excluded, final month included), which makes the purpose unambiguous. It does not explicitly differentiate itself from siblings, but the unique index-focused scope is clear enough among the calculo_* tools.

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 provides useful conditional guidance: if `valor` is provided, it returns the corrected value; if `incluir_valores` is true, it returns monthly variations. However, it does not explain when to prefer this tool over alternative calculation tools or when not to use it. Usage context is implied rather than explicitly contrasted with siblings.

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