platform_fee_comparison

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

No annotations are provided, so the description must convey behavioral traits. It indicates a pure calculation (compare net revenue) but does not explicitly state that it is read-only or non-destructive. It also does not describe any side effects, authentication needs, or rate limits. For a calculator, this is likely acceptable, but the description could be clearer about being a computation without external effects.

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 a single, front-loaded sentence that states the core purpose and lists the parameters. There is no redundant information, and it is appropriately short.

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 lacks an output schema, so the description should explain what the tool returns. It only says 'Compare net revenue' without specifying the format (e.g., a list, a table, a recommendation). It also does not mention any edge cases, currency assumptions, or what happens with invalid input. Given the lack of an output schema, this is a significant gap for the agent to know what to expect.

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 schema has no descriptions for parameters (0% coverage). The description adds that the input is 'itemPrice, shippingFee (optional)', which clarifies that shippingFee is not required and that both represent monetary values for a sale. This provides some context beyond the bare schema, but it does not explain units, formats, or how the values are used in the calculation.

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's function: 'Compare net revenue on Etsy, eBay, and PayPal for a given sale.' This is a specific verb (compare) and resource (net revenue across three named platforms), and it distinguishes itself from the sibling calculators (e.g., paypal_fee_calculator) by covering multiple platforms rather than a single one.

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 the tool is for comparing across three platforms, but it does not explicitly state when to use this tool versus the individual platform calculators. There is no mention of alternatives or conditions (e.g., 'Use this when you need to compare across platforms; use a single calculator for one platform only'). The intent is inferable but not spelled out.

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