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

With no annotations, the description must carry the full burden of behavioral disclosure. It only adds 'Browser-based tool,' which hints at a client-side UI but does not explain how profit is calculated, what fees are considered, or any limitations.

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 function without any redundant wording. It is appropriately short for the tool's simplicity.

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?

Given the absence of parameters and output schema, the description is minimally adequate, but it lacks specifics about which EC platforms are covered, what factors contribute to profit, and any assumptions in the comparison. This could matter when an agent selects among similar calculators.

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 tool has zero parameters, so the schema is vacuously complete. The description adds no parameter-related detail, but the baseline for 0 params is 4.

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 a specific action (compare) and resource (profits from selling the same product on various EC platforms). It distinguishes itself from sibling platform-specific calculators by focusing on cross-platform comparison.

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?

There is no guidance on when to use this tool versus the many alternative fee/profit calculators (e.g., rakuten-fee-calculator, shopify-profit-calculator, yahoo-shopping-calculator). The 'Browser-based tool' note only indicates format, not usage context.

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