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

With no annotations provided, the description carries the full burden. It discloses the outputs (net profit, margin, ROI, fee breakdown, break-even price) but does not mention underlying fee rate assumptions, the optional ad cost parameter, or any limitations. This gives functional transparency but leaves some behavioral details implicit.

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 concise, two sentences, front-loaded with the verb 'Calculate,' and every clause contributes useful information about inputs or outputs. No filler or redundant phrasing.

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?

Since there is no output schema, the description lists the return values (net profit, margin, ROI, fee breakdown, break-even price). It captures the essential workflow and is complete enough for a simple calculator. Minor gaps include not mentioning the optional adCost parameter or fee rate assumptions, but these are not critical for basic usage.

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 0%, so the description must compensate. It names price, COGS, and size tier and explains their role in the calculation. However, it omits adCost and referralRatePct, leaving those to be inferred from the schema. It adds some meaning beyond parameter names but does not fully cover all five parameters.

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 'Calculate Amazon FBA net profit, margin, and ROI for any product' with a specific verb and resource. It distinguishes itself from generic calculators by explicitly targeting Amazon FBA and mentioning the full fee breakdown.

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 clear usage context: 'Enter price, COGS, and size tier to see the full fee breakdown and your break-even price.' It tells the agent exactly what inputs to provide and what to expect, but it does not explicitly mention alternatives or situations where this tool should not be used.

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