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

With no annotations, the description carries the full disclosure burden. It reveals the paywall model (5 free trial calls per signed wallet), which is genuinely useful, but says nothing about output units (square units), precision, error behavior, or that both parameters are numeric strings rather than numbers.

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 functional content is a single short clause, which is front-loaded and not padded with prose. However, the pricing/emoji sentence consumes roughly half the description without helping the agent call the tool correctly.

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?

No output schema exists, no annotations exist, and schema coverage is 0%, so the description must supply the missing contract — yet it omits the formula (total vs lateral surface), units, and parameter formats. For a math tool whose whole value is a precise numeric answer, this is insufficient.

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% and the description never mentions height or radius, so no meaning is added beyond the bare property names. The two parameters are typed as strings with no format or unit guidance, leaving the input contract effectively undocumented.

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?

"Cone Surface: Surface area of cone" names the resource and the quantity computed, but it largely restates the tool name and does not disambiguate total surface area from lateral surface area, which matters given siblings like x402-cylinder-lateral-surface and x402-cone-volume.

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 when-to-use guidance, no note about when to prefer x402-cone-volume or x402-cone-frustum-volume, and no statement of prerequisites beyond the pricing line. The agent must infer selection purely from the name.

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