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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful operational context: pricing per successful call and an alternate HTTPS endpoint, though it does not discuss rate limits or output format.

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 purpose and uses concise sentences for examples, bounds, pricing, and endpoint. The example values are somewhat extra but serve as useful sanity checks rather than filler.

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 one-parameter math tool with annotations covering safety and no output schema, the description provides purpose, bounds, example return values, pricing, and an alternate endpoint. An agent has enough information to invoke it correctly without additional context.

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%, but there is only one parameter, and the description clarifies that n indexes the cumulative sum from F(0) through F(n) while noting the 0–16 bound. The schema already encodes min/max, so the description adds modest semantic value without fully documenting parameter behavior.

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 mathematical operation: the sum of Franel numbers F(0) through F(n). This is clear enough to distinguish it from a generic number tool, but it does not explicitly contrast with siblings like franel or franel_central.

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 does not say when to use this cumulative-sum tool instead of franel, franel_mod, or other Franel siblings. It only states the valid n range and gives example values, leaving the choice largely inferred from the tool name.

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