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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive. The description adds relevant operational context: cost $0.001 per successful call, x402/Solana payment, and an HTTPS endpoint. It does not contradict annotations, though it omits return format and error behavior.

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?

Front-loads the definition, then examples, range, and pricing/endpoint in short sentences. Most content earns its place, though the range merely repeats the schema min/max.

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 one-parameter mathematical predicate with annotations already covering safety and no output schema, the description provides enough to call it correctly: domain, examples, price, and alternate endpoint. The main residual gap is that the boolean return is implied by 'Whether' rather than explicitly stated.

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?

Only n is required; schema coverage is 0% and the schema itself has no descriptions. The description supplies the domain 'n runs from 1 to 1000000' and the mathematical role of n, but it does not explicitly restate type or define return semantics.

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 gives a precise predicate: whether the sum of bi-unitary divisors of n is less than 2n, with examples. It is clear what resource is tested, though it does not distinguish this from sibling tools such as biunitary_abundant, biunitary_perfect, or biunitary_sigma.

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?

No when-to-use or when-not-to-use guidance is given. The definition implies the property, but an agent gets no explicit routing versus biunitary_abundant/perfect/sigma or other divisor-sum tools.

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