validate.cusip

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

No annotations are provided, so the description must cover behavioral traits. It states the tool is 'deterministic' and describes the validation algorithm (mod-10 weighted check digit) and outputs (valid + check digit). This is good, but it does not explicitly state that the tool is read-only or has no side effects, which would be ideal for a validation tool.

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?

Two sentences provide all essential information: what it validates, the algorithm, and the expected output. No redundant text, and the purpose is front-loaded in the first sentence.

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?

Given the single parameter and no output schema, the description explains the core functionality and expected return values ('valid + check digit'). However, the return format is ambiguous (e.g., separate values or a combined object), and there is no mention of error handling or edge cases. For a simple validation, this is mostly complete.

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 input schema has 100% coverage with description '9-character CUSIP.' The description adds meaning by explaining 'US/Canada securities identifier' and the 'mod-10 weighted check digit' algorithm, which goes beyond the schema's simple type description.

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 specifies 'Validate a CUSIP (9-character US/Canada securities identifier) with its mod-10 weighted check digit', clearly identifying the verb (validate), resource (CUSIP), and scope (9-character, US/Canada). This distinguishes it from sibling validation tools for other identifiers like ISIN or ABA.

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 does not explicitly state when to use or avoid this tool versus alternatives. While the name and specificity imply usage for CUSIP validation, there is no guidance on prerequisites, error conditions, or comparisons to other validation tools.

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