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. It lists three capabilities — check, generate, factorize — but does not explain how the tool behaves, what it returns, or how the mode is selected. The description names the domain but not the behavioral contract.

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, front-loaded, and contains no filler. It repeats 'Prime' at the start, but overall it is efficiently structured for the limited content it provides.

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 utility that claims to check, generate, and factorize primes, the absence of parameters and any explanation of how to specify a number makes the tool effectively non-invocable. With no output schema and no annotations, the description is far too incomplete for an agent to call this tool correctly.

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 the baseline is 4. The description does not conflict with the schema, though it also does not clarify how a number to check or factorize would be supplied — that gap is more relevant to contextual completeness.

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 says 'Prime number utilities — check, generate, factorize,' which conveys a broad category rather than a single precise operation. It is clear enough to know the tool involves prime numbers, but it does not distinguish this tool from related siblings like x402-is-prime, x402-prime-factors, and x402-prime-series.

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 x402-prime versus the many prime-focused sibling tools. No alternatives, exclusions, or conditions are mentioned, so an agent cannot determine whether to use this tool or a more specific sibling.

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