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

With no annotations or output schema, the description carries the transparency burden. It states what is returned (national holidays with dates and weekdays) and scopes the data to 2026. It could mention output format or limitations, but it accurately discloses the core behavior.

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?

A single sentence that front-loads the action and resource, with no filler. Every element — country, year, and data fields — earns its place.

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 zero-parameter, fixed-data getter, the description is nearly complete: it identifies the country, year, and return contents. Only the exact response shape, such as list format, is left unspecified, which is minor given the simple no-output-schema case.

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?

The input schema has zero parameters with 100% coverage, and the rubric sets a baseline of 4. The description correctly implies no configuration is needed by describing a fixed dataset of 2026 national holidays.

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 the verb 'Retorna' and names the precise resource: Brazilian national holidays for 2026, including dates and weekdays. This clearly identifies the tool and separates it from the finance and calculation focused sibling 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 scope is explicit — national holidays of Brazil, year 2026 — so an agent can tell when this tool applies. It does not name alternatives or spell out when not to use it, but no sibling tool offers holiday data and the zero-parameter design makes the intended use obvious.

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