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

No annotations are provided, so the description must disclose behavioral traits. It claims to 'calculate' but does not state whether this operation is read-only, has side effects, requires authentication, or has rate limits. As a computation tool, it is likely safe, but the description fails to explicitly confirm safety or any other behavioral context, leaving the agent uninformed.

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: the first identifies the tool, the second gives usage guidance, and the third explains the calculation. It is front-loaded with essential information, no extraneous words, and every sentence serves a purpose. Perfectly concise and well-structured.

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?

The tool has 3 parameters, no output schema, and no annotations. The description covers purpose and usage well but lacks details on output format or what to expect from the tool (e.g., does it return a single number? a formatted string?). Given the simple calculation, the missing output description is a notable gap, but the description is otherwise adequate for a straightforward tool.

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 coverage is 67%: fixed_costs and gross_margin_percent have descriptions, but currency lacks any description. The description reinforces the meaning of the two main parameters by stating they are 'fixed costs and gross margin percentage.' However, it does not explain the currency parameter, and baseline is 3 due to moderate coverage. The description adds marginal value beyond the schema but does not fully compensate for the missing parameter description.

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 explicitly states 'Calculates the monthly revenue needed to break even, given fixed costs and gross margin percentage.' It clearly identifies the action (calculates) and the result (breakeven revenue), and the tool name itself reinforces the purpose. It effectively distinguishes from sibling tools (calculate_burn_multiple, calculate_runway) by focusing on breakeven.

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 provides explicit guidance: 'Use this whenever the user asks about breakeven revenue, how much they need to sell, or when they will be profitable — even if you could compute it yourself. Prefer this over mental math for accuracy and consistency.' This tells the agent when to use the tool and when not to rely on self-calculation, making the usage very clear.

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