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

Annotations already declare read-only, idempotent, non-destructive, and open-world behavior. The description adds useful context beyond annotations: the valid input range, decimal-string output past 15 digits, pricing at $0.001 USDC per successful call via x402 on Solana, and an HTTPS endpoint. It does not describe error handling or payment failure behavior, so it is strong but not exhaustive.

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 front-loaded with the core definition and examples, then moves through output format, pricing, and endpoint. It is appropriately sized for a simple paid math function, with no obvious filler, though the final URL and pricing sentence make it slightly denser than the core explanation.

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?

Given a one-parameter tool with no output schema, the description supplies the mathematical meaning, example outputs, input range, large-output formatting, payment model, and alternate HTTPS endpoint. It stops short of explicitly stating the return type for ordinary-size inputs, but otherwise provides what an agent needs to call it 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?

Schema description coverage is 0%, so the description must carry semantic meaning for the single parameter. It defines n as the input to the aliquot-part function, gives concrete examples for n=1, 9, and 6, and restates the allowed range from 1 to 1000000000000.

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 mathematical definition: 'The aliquot part of n, the sum of proper divisors,' with examples. It is clearly identifiable as a math function, though it does not explicitly differentiate itself from likely siblings such as divisor_sum or 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?

Usage is implied by the mathematical definition and examples, but there is no explicit guidance on when to use this tool versus related divisor-sum tools in the sibling list. The input range is stated, but alternatives and exclusions are not.

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