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

Annotations already declare the operation read-only, idempotent, open-world, and non-destructive. The description adds useful operational context beyond annotations: the valid index range, pricing per successful call, and the equivalent HTTPS endpoint. It does not specify error behavior or the exact return representation, but given the annotation coverage this is a solid disclosure.

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 core definition and recurrence before adding examples, range, pricing, and endpoint. Every sentence adds relevant value for an agent deciding whether and how to call the tool.

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 mathematical lookup with no output schema, the description is nearly complete: it defines the sequence, index base, valid range, examples, and payment/HTTP access details. The only minor gap is that it does not explicitly state that the call returns the integer term a(n), though the examples strongly imply a scalar result.

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 the schema itself defines n as an integer bounded from 1 to 60. The description compensates by clarifying that counting starts at 1 and by giving concrete examples such as a(4)=2 and a(15)=129, which meaningfully explains the parameter beyond its type and bounds.

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 the specific resource and operation: the Narayana cow sequence value at index n. It even gives the recurrence and sample terms, making the mathematical purpose unambiguous. It does not explicitly differentiate itself from closely named siblings such as narayana, narayana_row, or cows_index, so it falls short of a 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?

The range 'n runs from 1 to 60' and the sequence definition imply when this tool is applicable, but there is no explicit guidance on when to use it versus siblings like narayana, cows_next, cows_sum, or cows_index. No when-not-to-use or alternative-selection advice is provided.

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