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

With no annotations, the description carries the full burden, and it delivers: it discloses the exact formula, the conversion factor, and the meaning of clock hours. It does not state the return format, but for a calculation tool the output (the additional amount in R$) is strongly implied by the formula and context.

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?

Two sentences with all information front-loaded: the formula first, then parameter requirements. Every clause earns its place, and there is no redundant repetition of schema content.

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 three simple parameters, full schema coverage, and no output schema, the description is nearly complete: it states the calculation, parameters, optional values, and naming conventions. A small gap is that it does not explicitly say the result is the monthly additional value in R$, but this is easily inferred from the formula.

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 100%, so the schema fully documents salary, monthly_hours, and night_clock_hours. The description adds the 1.14 conversion context and reinforces required/optional status, but does not add substantial meaning per parameter beyond what the schema already provides.

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 uses a specific verb ('Calcula') and resource ('adicional noturno urbano'), and goes further by specifying the exact calculation components: 20% over daytime wage plus the reduced night-hour effect (52min30s → 1.14 paid hours). This is easily distinguishable from sibling calculators like calculate_overtime or calculate_hourly_wage.

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 clearly establishes the use case (urban night shift additional, 22h-5h) and tells the agent which parameters are required versus optional, plus to use exact English names. It does not name alternatives or exclusion conditions, but the specialized scope makes when-to-use unambiguous.

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