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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses cash-only behavior, total-vs-item rounding, post-tax order, exact digit rounding rules, string-as-dollars vs number-as-cents coercion, and a legal caveat. No contradiction with annotations.

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?

Core operational details are front-loaded and well organized. The 'WHY DELEGATE THIS' section is slightly redundant, but it adds misconception context and a technical warning, so it earns most of its length.

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?

The common cash-rounding path is thoroughly documented, including input formats and exclusions. Yet there is no output schema and no statement of the return value, and the rule parameter's effect on the result is left unexplained, so non-default invocations are under-specified.

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?

The description adds useful semantics for subtotal input types and reinforces tender/tax behavior. However, the 'rule' parameter is not described; the stated digit-rounding behavior is only the default and does not explain symmetric, always-down, always-up, or none.

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 opens with a precise verb+resource: settle a transaction by computing tax on the exact subtotal and rounding the final total to the nearest nickel, cash only. This unambiguous scope is clearly distinct from generic rounding tools.

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?

It explicitly states when to use (cash, after tax, on the total) and when not to (card, EFT, gift-card stay priced to the cent). It does not name a sibling tool as the alternative, so the routing guidance stops just short of being fully explicit.

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