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

With no annotations provided, the description carries the full behavioral burden. It explains that the tool computes required investment for a target monthly dividend income, which is useful. However, it does not disclose calculation assumptions, output format, or limitations such as whether the annual yield is applied directly without monthly compounding.

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 compact and front-loaded: the core purpose appears in the first sentence, followed by required/optional parameters and a naming instruction. Every sentence contributes necessary information with no filler.

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 calculator tool, the description combined with the fully-covered schema is mostly complete for invocation. The main gap is the absence of any statement about what the result represents or how it is returned, since there is no output schema to fill that gap.

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 already provides 100% parameter descriptions and defaults, so the description adds little semantic value beyond restating required vs optional parameters. The note to use exact English names is a minor practical addition but does not deepen understanding of any parameter.

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 clearly states the function: 'quanto precisa investir pra receber X por mês em dividendos de ações ou FIIs' — a specific goal of computing required investment for a target monthly dividend income. It is clear but does not explicitly differentiate itself from near-sibling tools such as calculate_dividend_income_goal.

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 implies when to use the tool through the stated scenario, and it lists required vs optional parameters, including the instruction to use exact English parameter names. However, it offers no explicit guidance on when to choose this tool over alternatives like calculate_dividend_income_goal or calculate_investment_return.

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