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

Annotations already cover the safety profile: readOnly, idempotent, openWorld, and non-destructive. The description adds important invocation context beyond annotations: the price is $0.001 USDC per successful call via x402 on Solana, and an equivalent HTTPS endpoint is provided.

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 front-loaded, followed by useful examples, input bounds, pricing, and an alternate endpoint. It is compact for the amount of relevant information, though the examples and endpoint details make it slightly longer than strictly necessary.

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 simple one-parameter predicate with annotations and no output schema, the description is largely complete: it defines the property, gives examples, states the input range, and discloses payment and endpoint details. The main missing piece is explicit return-value wording and sibling routing guidance.

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?

There is one parameter, n, and schema description coverage is 0%. The description compensates somewhat by stating n ranges from 0 to 999999999999999 and by giving example values, but the range duplicates the schema constraints and it does not clarify edge cases such as leading zeros or how k is counted.

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 states a precise predicate: it checks whether the first k digits of n are a multiple of k for every k. The examples make the property concrete. It does not explicitly distinguish this check from the sibling polydivisible_count, so it falls short of a 5.

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?

The description gives examples of n values that do and do not satisfy the property, plus the valid input range, but it never says when to use this tool versus alternatives such as polydivisible_count. Usage is only implicit from the predicate wording.

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