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

With no annotations provided, the description carries the full behavioral burden and mostly fails: it does not state the input type expectations (both params are strings), whether 1 or n itself is excluded, what the return value looks like, or error behavior for zero/negative input. The one genuinely useful behavioral disclosure is the '5 free trial calls per signed wallet' payment/auth note, which explains the x402 billing model.

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?

Two short, front-loaded sentences with no filler; the definition comes first and the pricing note second. It is efficient, though the emoji/pricing line is somewhat separate from the core semantic content.

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 arithmetic tool this could be near-complete, but with zero annotations, 0% schema coverage, two ambiguous optional string parameters, and no output schema, an agent has too little to call it correctly. The definition should at minimum state which parameter supplies the integer and how large values are handled.

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% and the description never mentions either parameter. An agent cannot tell whether to supply 'n' or 'value', whether both are needed, or what format (big-integer string?) they take — this is exactly the case where the description must compensate and does not.

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 specific mathematical operation — the sum of proper divisors — and even parenthesizes the canonical name, so the resource is unambiguous. It does not distinguish this from the close sibling x402-aliquot-sequence or x402-is-perfect-number, which an agent would need to choose between, keeping it below 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?

There is no guidance on when to call this versus the many adjacent number-theory siblings (aliquot-sequence, abundant/deficient/perfect checks). The only contextual statement is a pricing note about free trial calls, which says nothing about task selection.

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