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

No annotations are provided, so the description carries the full burden of behavioral disclosure, yet it discloses nothing beyond the computed quantity. It does not state the formula (total vs lateral surface area), whether inputs are expected, what the return value looks like, or any units or edge cases. It does not contradict any annotation (none exist), but it adds essentially zero behavioral context.

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?

At seven words, the text is brief, but this is under-specification rather than efficient conciseness. The first clause 'Cone Surface' restates the name and the second 'Surface area of cone' merely expands it, so no sentence carries operative guidance (usage, inputs, formula, alternatives). Short but information-poor.

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 computation tool with no annotations, no output schema, and an empty input schema, the description needed to state required inputs and what the result is, and it supplies neither. An agent cannot correctly invoke this tool — it does not know what arguments to provide or what output to expect. The description covers only the object of computation and nothing else.

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 schema is empty, making description coverage trivially 100%, and with 0 parameters the baseline is 4. However, for a surface-area calculation that inherently requires radius and height (or slant height), the description's total silence on required inputs is a real gap — an agent has no way to know what values to supply. With no parameters to annotate, the description adds no meaning beyond the empty schema, warranting a deduction from baseline.

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 the resource (cone) and the quantity (surface area), which is enough to tell it apart from volume tools like x402-cone-volume. However, 'Cone Surface: Surface area of cone.' is largely a restatement of the tool name and does nothing to distinguish it from the many geometry siblings (cone-frustum-volume, cylinder-surface, sphere-surface). It is clear but minimal, lacking even a verb or any qualifying detail.

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?

The description provides zero guidance on when to choose this tool over alternatives. With thousands of siblings including x402-cone-volume, x402-cone-frustum-volume, x402-cylinder-surface, and x402-area, the agent receives no exclusions, no routing conditions, and no context for selection. The agent must infer usage entirely from the name.

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