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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false. The description adds useful behavioral context beyond those: pricing ($0.001 USDC per successful call), x402/Solana payment, and an HTTPS endpoint. It does not spell out the return value explicitly, but 'Whether...' implies a boolean result.

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 examples, exclusions, range, and payment details with no filler. Every sentence contributes to understanding or invocation.

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 boolean number-property predicate with one schema-enforced parameter, no output schema, and annotations covering safety, the description provides enough context: definition, examples, domain, pricing, and alternate endpoint. Return shape is adequately implied by the opening 'Whether n is...' phrasing.

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 required parameter, n, and the description gives its range and examples of valid values. However, with 0% schema description coverage, it does not add much semantic detail beyond what the schema already constrains, such as explicit type wording or behavior for invalid inputs.

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: whether n is a composite hoax number, defines the digit-sum condition, gives examples, and explicitly excludes primes and distinguishes from Smith numbers. This is enough for an agent to identify the tool as a number-property predicate rather than a sibling sequence calculator.

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?

It supplies the valid input domain (1 to 1000000) and contrasts hoax numbers with Smith numbers and primes, which clarifies when the tool applies. It does not explicitly route to named sibling alternatives or state when not to use it, so it falls short of full usage guidance.

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