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, and it reveals nothing. It does not state what the tool returns, whether it computes an angle for a given side count, what units are used, or any other behavioral trait. The description adds zero information beyond the name itself.

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 only four words, but this is under-specification rather than conciseness — no sentence earns its place because no sentence conveys information. It lacks the word count needed to state even the basic function of the tool.

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?

This is a completely inadequate definition. There are no annotations, no output schema, and a tautological description; the agent has nothing to infer what 'exterior' means (presumably exterior angle of a regular polygon), what argument format is expected, or what the result looks like. Among thousands of siblings, this tool is entirely indistinguishable.

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 has zero parameters, so schema description coverage is trivially 100% and there is nothing confusing to document. The 0-param baseline supports a neutral score, but the description adds no meaning about the tool's computation that would help an agent understand what inputs or outputs are involved.

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, "Regular Polygon Exterior: Regular Polygon Exterior," is a pure tautology that merely restates the tool name in a colon-separated format. It contains no verb, no explanation of what is computed, and no differentiation from closely related siblings like x402-regular-polygon-interior, x402-regular-polygon-area, and x402-regular-polygon-perimeter.

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 whatsoever on when to use this tool versus the numerous polygon-related alternatives. An agent has no way to determine whether to pick this over the interior-angle, area, or perimeter variants — no mention of use cases, exclusions, or alternatives is provided.

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