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

The annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful behavioral context beyond that: the $0.001 USDC x402 payment per successful call and the equivalent HTTPS endpoint. It does not explain failure charging or rate limits, but it covers the important payment semantics.

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 compact and front-loaded with the operation and parameters, followed by range constraints, pricing, and the HTTPS alternative. Every sentence serves either selection, invocation, or payment transparency.

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 range-sum tool with annotations covering safety and no output schema, the description is largely complete: it covers purpose, parameters, bounds, payment, and alternate transport. The only minor gap is that it does not explicitly describe the return format beyond implying a sum.

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 parameter meaning, and it largely does: it defines the inclusive lo-to-hi range, states lo must not pass hi, gives the 0-8192 index bound, and maps seq values j/l to Jacobsthal/Jacobsthal-Lucas sequences. It does not explicitly restate the default seq value, but the core semantics are covered.

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 specific operation and resource: summing Jacobsthal or Jacobsthal-Lucas numbers over an inclusive index range. The seq parameter distinguishes the two sequence families, and 'sum' distinguishes it from sibling tools that return individual terms or transform sequences.

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 gives operational constraints such as lo <= hi and the 0-8192 index range, which implies when the tool is applicable. However, it does not explicitly route the agent away from siblings like jacobsthal, jacobsthal_lucas, or jacobsthal_add, so usage guidance is only implied.

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