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

Annotations already declare this as a read-only, idempotent, non-destructive operation. The description adds useful context beyond that: it is an x402-paid API costing $0.001 USDC per successful call and is also available over HTTPS. It does not describe error behavior or response type, but the examples clarify the computed output.

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 definition is front-loaded with the core computation, then examples, domain, pricing, and endpoint. Every sentence is useful and there is no wasted text.

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 tool with no output schema, the description defines the result, gives examples, and states the input domain and payment model. It is nearly complete, though it could explicitly state the return type or error behavior for out-of-range input.

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?

With zero schema description coverage, the description compensates by saying n is the starting integer and runs from 1 to 1,000,000. The examples further ground what n means. It repeats the schema's numeric range, but for a single-parameter tool it gives enough semantic context.

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 largest value on the Collatz trajectory from n through 1, including n. The examples make the computation unambiguous. However, it does not distinguish this tool from the very close sibling `collatz_max`, which likely computes a similar or identical value.

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 the valid range for n and examples, but it provides no explicit guidance about when to use this tool instead of related Collatz siblings such as `collatz_max`, `collatz_length`, or `collatz_steps`. The HTTPS endpoint is an access alternative, not tool-selection guidance.

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