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

With no annotations provided, the description carries the full burden for behavioral disclosure. It does not state that the tool returns a numeric value, what units are used, or that it computes a formula like 2πrh. It only restates a label, providing no practical 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?

The description is very short and front-loaded, but the first phrase 'Cylinder Lateral Surface' needlessly repeats the tool name, and 'Surface area of cylinder lateral' adds minimal new information. It is concise in length but not efficiently meaningful.

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 tool with no output schema, no annotations, and an empty input schema, the description is insufficient. It does not describe the return format, the distinction from total cylinder surface area, or why it takes no parameters. An agent cannot confidently predict the result or choose it over the many sibling geometry tools.

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 input schema has 0 parameters, and the rule grants a baseline of 4 for zero-parameter tools. The description does not need to elaborate on parameters, though it could have explained why no inputs are required (e.g., a constant or pre-configured value), but this is not deducted given the 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 'Cylinder Lateral Surface: Surface area of cylinder lateral.' is essentially a rephrasing of the tool name. It states what the resource is rather than what the tool does, with no verb and no explicit scope (e.g., excludes top/bottom). This borders on tautology, since the name already conveys 'lateral surface'.

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 about when to use this tool versus its siblings, including x402-cylinder-surface and x402-cylinder-volume. No mention of use cases, prerequisites, or alternatives appears anywhere in the description.

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