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

With no annotations provided, the description carries the burden of behavioral disclosure. It does this well by revealing the exact calculation formula, noting that fulfillment fees apply only to FBA, and indicating that return rate is not directly deducted. This gives agents important behavioral context beyond the schema, though it does not cover every edge case.

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 two compact sentences: the first front-loads the outputs, the second states the formula. Every phrase earns its place, and there is no filler or repetition of schema boilerplate.

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 calculator with 7 parameters but only 2 required, the schema defaults and per-parameter descriptions, combined with the description's formula, provide enough to invoke the tool correctly. The output schema covers return-value details. The main missing element is explicit sibling-selection guidance, which is a meaningful but not fatal 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?

Schema description coverage is 100%, so the baseline is 3. The description adds relational meaning by tying parameters together in the formula: sell_price minus landed_cost, platform commission, FBA fulfillment fee, and advertising cost. This is valuable beyond the individual per-parameter schema descriptions.

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 uses a specific verb ('估算' / estimate) and clearly names the resources: per-unit net profit, net margin, ROI, and breakeven ACoS. It also provides the profit formula, making the purpose concrete. It does not explicitly differentiate itself from siblings like breakeven_price, so it falls short of a 5.

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 gives no explicit guidance on when to use this tool versus breakeven_price, the main sibling alternative. The only alternative reference is buried in a parameter description ('可用 calculate_landed_cost 得到'), which mentions a data source but not selection criteria. Usage context is largely left to inference.

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