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

No annotations are provided, so the description carries full burden. It accurately describes the tool as a calculation (no destructive or state-changing behavior). Could be more explicit about being read-only, but for a simple math tool this is adequate.

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, front-loading the core purpose. The first sentence is slightly redundant with the name, but overall it is efficient and scannable with no unnecessary words.

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 calculation tool with three parameters and no output schema, the description explains what it computes and when to use it. It does not describe the return format, but that is not critical. It is complete enough for the agent to understand its role.

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 67% with descriptions for fixed_costs and gross_margin_percent. The description does not add additional meaning beyond stating what the tool calculates. The optional currency parameter has only a default value with no description, and the description does not elaborate on parameter formats or constraints.

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 tool calculates monthly breakeven revenue given fixed costs and gross margin. It distinguishes from sibling tools by naming specific use cases (breakeven revenue, profitability) and contrasts with mental math.

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?

Explicitly advises using this tool whenever the user asks about breakeven, revenue needed to sell, or when profitable, even if the agent could compute it. Preferring over mental math for accuracy provides clear context. No explicit when-not-to-use, but the guidance is sufficient.

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