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

With no annotations provided, the description carries the burden of explaining behavior. It discloses the methodology (official PNAD Contínua 2024 table, interpolation between class averages), which tells the agent the result is an estimate based on a specific source. It does not state the output shape or edge-case behavior, but the core calculation and its limitations are 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?

Three sentences with a clear order: what the tool does, what data/method it uses, and how to pass the parameters. The core purpose is front-loaded and every sentence contributes information. No filler or repetition.

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 explains the inputs, the source data, and the estimation method well enough for an agent to call it. It could specify the output format (e.g., numeric percentile 0–100 or decimal), but the phrase 'em que percentil... está' makes the intended return reasonably clear.

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% and both parameters already have clear descriptions with units and bounds. The description mostly repeats the required/optional status and parameter names, though it usefully insists on the exact English parameter names. This meets the baseline but adds little 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 opens with a specific verb and resource: it estimates a Brazilian household's income percentile. It clearly names the two inputs and the underlying PNAD/IBGE table, so an agent can tell it apart from the many sibling calculators. It does not explicitly contrast against a sibling, so it falls just short of a 5.

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 use case is implied by the first sentence: call this when you need to know a household's percentile in the Brazilian income distribution. There is no explicit when-to-use/when-not-to-use guidance or mention of alternatives among the sibling calculators, so the guidance is adequate but not strong.

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