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

No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing: not the return shape (booleans, details), not input expectations, not edge cases. The repetition of the name adds 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?

The definition is tiny, but it is not concise in a useful way — it is under-specified and redundant, repeating the name with a colon rather than front-loading any meaningful purpose.

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?

With no annotations and no output schema, the description had to convey the check's semantics (what a Kaprekar number is, expected input) and return behavior, and it conveys none of that. It is completely inadequate even for a one-parameter tool.

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?

Schema description coverage is 100% for the single 'value' parameter, so the schema technically documents it. The description adds nothing about the parameter (e.g., numeric range, string vs number), but the baseline for full coverage is 3.

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 'Is Kaprekar: Is Kaprekar' merely restates the tool name, which is essentially a tautology. It never states what constitutes a Kaprekar number or what the tool actually checks. It also fails to distinguish itself from the near-identical sibling 'x402-is-kaprekar-number'.

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 on when to use this tool, what input format is expected, or how it differs from the closely related 'x402-is-kaprekar-number' sibling. The agent is left to infer everything.

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