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

Annotations already establish that this is read-only, idempotent, non-destructive, and open-world. The description adds useful beyond-schema context: pricing per successful call, x402/Solana payment details, and an HTTPS endpoint alternative. It does not describe failure or payment-error behavior, but the key behavioral traits are covered.

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 computation and examples, then adds practical constraints, pricing, and transport. Every sentence contributes useful information without waste.

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 pure-function tool with no output schema, the description gives enough to invoke it correctly: computation, range, examples, and cost/transport details. It could explicitly state the return type or error behavior, but no critical invocation information is missing.

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%, so the description must carry parameter meaning. It defines n as the number of initial terms summed, states the valid range 1 to 60, and gives examples that reinforce what n controls. This compensates well for the schema gap, though it could explicitly note the return type.

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 verb and resource: the sum of the first n Narayana cow numbers. The examples and range make the computation unambiguous, and 'sum' clearly distinguishes it from sibling tools like cows_next, cows_index, or narayana_cows even without naming them explicitly.

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 implies when to use the tool by defining the cumulative-sum operation and valid n range, but it does not name alternatives such as cows_index or cows_next or explain when not to use this tool. Usage is inferable but not explicitly guided.

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