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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only states the general purpose. It does not explain how inputs are supplied, what formula is used, what the return value looks like, or whether it handles edge cases like invalid side counts. The absence of parameters in the schema makes this lack of behavioral context more damaging.

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 extremely brief, but brevity is achieved by restating the tool name rather than by conveying meaningful information. It reads as under-specification, not disciplined conciseness; the sentence does not earn its place because it adds no value over the name itself.

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 zero-parameter tool with no annotations and no output schema, the description must explain how and when the agent should invoke it, yet it only repeats the tool's purpose. An agent cannot determine how to provide the number of sides and side length, what to expect in return, or why this tool differs from the many related 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 zero parameters, so there are no parameter semantics for the description to clarify; the rubric baseline for no parameters is 4. However, the description also fails to note that inputs must be inferred from the prompt context, which is a structural gap beyond schema semantics.

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 "Area of regular polygon" simply restates the tool name with different word order; it is a tautology that adds no new information about the tool's function. It does not specify the shape inputs (number of sides, side length) nor distinguish it from adjacent tools like x402-regular-polygon-perimeter or x402-polygon-area.

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 alternatives such as x402-polygon-area, x402-triangle-area, or x402-regular-polygon-perimeter. The description never mentions conditions, prerequisites, or exclusions, leaving the agent to infer usage solely from the name.

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