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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld. The description adds useful behavioral context beyond that: earliest-divisor tie-breaking, rejection of odd sums and missing splits, valid n range 1–2000, cost per successful call, and an HTTPS endpoint. It does not detail error response format, but the extra context is substantial.

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 front-loads the core purpose and output format, then adds examples, constraints, range, price, and endpoint. Most sentences carry useful information, though the pricing and endpoint details are somewhat peripheral to the computational semantics.

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 computational tool with no output schema and supportive annotations, the description is largely complete. It explains the result format, gives examples, and covers key rejection cases and valid input range, leaving only minor gaps around exact error responses.

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 coverage is 0% and the single parameter lacks a schema description, so the description must compensate. It does so by stating that n runs from 1 to 2000 and by showing example values, though it does not explicitly define n as the input integer whose divisors are considered.

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 clearly states that the tool returns one divisor subset summing to half the divisor-sum, formatted comma-separated, and choosing the earliest divisors. It gives concrete examples for n=6 and n=20. However, it does not explicitly distinguish this from sibling tools like zumkeller, zumkeller_half, zumkeller_count, or zumkeller_odd.

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 explains what the tool returns and notes rejection conditions for odd sums and missing splits, but it gives no guidance on when to use this tool versus sibling Zumkeller tools. There is no mention of alternatives or selection criteria.

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