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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It only restates the calculation modes and parameter presence; it does not describe the return shape, behavior when both or neither optional parameter is supplied, rounding, or error handling. With no output schema, these are meaningful gaps.

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 short, front-loaded with the core function, and contains no filler. The parameter summary and 'use exactly these names' reminder are slightly redundant with the schema, but they are concise and serve as useful guardrails.

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 simple three-parameter calculator, the essential invocation context is present. However, without an output schema, the description omits the return format and edge-case behavior such as supplying both optional parameters or neither, leaving some uncertainty for the agent.

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 already documents each parameter and the exclusivity between final_price and discount_percent. The description adds only a redundant required/optional summary and the instruction to use exact English names, which does not meaningfully improve on 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 'Calcula desconto' and immediately clarifies the two supported directions: final price from a percentage, or percentage from a final price. This makes the tool's specific function unmistakable and distinguishes it from the many sibling calculate_* 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?

It clearly states that original_price is required and discount_percent/final_price are optional, and it frames the two main usage scenarios. It does not name alternative tools or explicit exclusion conditions, but the intended use context is clear enough for selection.

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