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

No annotations are provided, so the description carries the full behavioral burden. It discloses the core computation outputs and adds a useful cost notice (x402 price $0.001/call), but it omits output format, rounding behavior, and edge-case handling.

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 definition is compact and front-loads the calculation before appending the payment detail. The aside about 'the two numbers people constantly mix up' adds mild educational value without derailing the main instruction.

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 low-complexity two-parameter calculator with no output schema, the description names the computed values but does not describe the return structure, numeric precision, or handling of zero/negative inputs. It is adequate but incomplete.

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 coverage is 100%, so the schema already documents both parameters. The description adds minor clarity by calling cost a 'unit cost' and price a 'selling price', but does not contribute units, currency, or validation rules beyond the schema.

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 verb (Calculate) and resources (gross profit, profit margin, markup) scoped to cost and selling price. It does not explicitly differentiate itself from sibling calculators like finance_roi_calculator or calculators_percentage_calculator, so it falls just short of the top score.

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 explicit when-to-use or when-not-to-use guidance, nor any mention of alternative tools. The role is implied by the calculation description, but the definition provides no routing signals for choosing this over sibling finance or percentage calculators.

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