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 implies a pure computation from four inputs but says nothing about return format, precision, assumed compounding convention, or error conditions for invalid inputs.

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 purpose is front-loaded in a single compact sentence followed by a short promotional note. Little waste, though the emoji trial line adds no functional value.

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 simple four-input math tool with no output schema and no annotations, the description covers the inputs and the operation adequately. It falls short on return-value and unit semantics, which an agent would need to interpret results correctly.

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 0%, so the description must compensate. It names all four fields and adds unit hints ('coupon percent', 'rate percent'), but leaves 'face' and 'years' format unstated and does not clarify that all values are passed as strings.

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?

States a specific verb+resource: 'Computes bond convexity,' with the exact inputs it consumes. An agent can identify the operation clearly, but the description never differentiates from closely related siblings such as x402-bond-duration, x402-bond-price, and x402-bond-yield, which an agent may confuse when choosing.

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 sibling bond tools, nor any prerequisites or context. The only extra text ('5 free trial calls per signed wallet') is billing info, not usage direction.

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