validate_cuil

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

Annotations already indicate readOnlyHint=true and idempotentHint=true, so the tool is safe and idempotent. The description adds behavioral details: it uses a weighted modulo-11 checksum and returns a specific success/failure object. No contradictions, and it gives useful output format information beyond 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?

The description is concise at four sentences, front-loads the key action, and every sentence adds value. No fluff, efficient communication.

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 simplicity of the tool (one parameter, defined output schema), the description is complete. It covers purpose, usage context, algorithm hint, and output format. No gaps.

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 100% with a clear description and example for the 'cuil' parameter. The tool description adds context about the meaning of CUIL in Argentina but does not add parameter-specific details beyond what the schema provides. Baseline 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 clearly identifies the tool as a validator for Argentine CUIL, explains what CUIL is, and distinguishes it from siblings like validate_cuit and validate_cpf by specifying the country and checksum. The verb 'validates' plus specific resource makes purpose unambiguous.

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 explicitly states when to use: 'when processing Argentine payroll, employment contracts, or any social security compliance workflow.' This provides clear context, though there is no explicit exclusion or alternative mentioned, but siblings serve as alternatives.

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