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

The annotations already declare openWorldHint, idempotentHint, and destructiveHint; the description adds important context that this is a paid x402 endpoint requiring an X-Bazaar-Key and costing 0.01 USDC. It does not explain charging failure behavior or whether repeated calls are billed again, but the payment/auth context is valuable beyond annotations.

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 with no wasted wording. The payment prefix and the computational purpose are both stated efficiently.

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 Black-Scholes calculator, the description and schema are insufficient for correct invocation because the schema exposes only spot_price and allows additionalProperties without documenting required inputs like strike, time to expiry, volatility, rate, or option type. It does list the outputs, but without an output schema and without input guidance, an agent cannot reliably call it.

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% for the single declared parameter, so the schema already explains spot_price as the underlying spot price. The description adds no further parameter meaning and does not explain how additional BSM inputs such as strike, volatility, or option type should be supplied via additionalProperties.

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 names a specific verb and resource: compute theoretical European Call/Put prices and Delta, Gamma, and Vega using Black-Scholes-Merton. It is clearly distinguishable from unrelated sibling tools, though it does not explicitly route against nearby finance calculators.

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?

It states what the tool computes but gives no explicit guidance on when to use it versus sibling finance or option-related calculators. There are no exclusions, prerequisites, or alternative-tool references to help selection.

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