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

No annotations are provided, so the description carries the behavioral disclosure burden. It clearly explains the core behavior: interest is always computed on principal, never on accumulated interest, and notes that this differs from real credit contracts. This goes beyond the schema and helps the agent understand the calculation semantics.

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 three sentences with the formula front-loaded, followed by the key behavioral warning and parameter guidance. Every sentence contributes meaningful information with no fluff.

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 calculation tool without an output schema, the formula and behavioral notes are sufficient for an agent to understand what the tool does and what it returns. The only minor gap is not explicitly stating the default for rate_type, though that information is present in the schema.

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 all parameters effectively. The description adds only a restatement of which parameters are required versus optional and emphasizes using exact English names, which is useful but does not substantially deepen parameter meaning.

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 states a specific verb and resource ('Calcula juros simples') and provides the exact formula. It also distinguishes the tool from compound-interest siblings by explicitly saying interest applies only to principal and never to accumulated interest.

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 lists required and optional parameters and instructs to use exact English names, which helps invocation. However, it does not explicitly say when to choose this tool over calculate_compound_interest or other finance calculators; it only implies the distinction by describing simple-interest behavior.

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