US late-fee ceilings by state

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, and the description neither contradicts nor merely restates them. It adds meaningful behavioral nuance: results are 'statute-verified conservative safe floors,' so they may understate rather than overstate permissible rates, and invocation is free. This is useful context beyond what the structured annotations provide.

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 short and front-loaded with the core purpose, immediately followed by the useful data-quality caveat. The phrase 'Free, costs no credits' is slightly redundant, but the overall structure is efficient and avoids unnecessary detail. Nearly every clause earns its place.

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-optional-parameter lookup with no output schema, the description states what will be returned—the ceiling and the statute cite—and includes the relevant caveat about conservative floors. The all-51-rows default is already covered by the schema. No significant missing context prevents an agent from using this tool correctly.

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 single optional 'state' parameter is fully documented in the input schema, including the two-letter USPS format and the omit-for-all-51-rows behavior. The description adds no additional parameter-level meaning beyond reinforcing that the lookup is state-scoped. With 100% schema coverage, a baseline of 3 is appropriate.

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 concrete action, 'Look up,' and specifies the exact resource: the maximum late-fee/interest rate a US state allows on commercial B2B invoices, along with the statute cite. It also adds 'statute-verified conservative safe floors,' which helps distinguish this from a generic legal or calculation tool. Compared with siblings like parserail_dunning or parserail_extract, the scope is unmistakable.

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 clearly conveys when this tool is appropriate: when an agent needs a state's allowed commercial late-fee ceiling or statute citation. It does not explicitly name alternative tools or state when not to use it, but the commercial/B2B qualifier implicitly rules out consumer or personal contexts. The 'free, costs no credits' note also helps agents decide whether to invoke it.

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