Validate Tax Id

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

With no annotations, the description carries the full burden, and it delivers: it states check-digit verification is conditional, discloses the Mexico RFC exception and the check_digit_verified:false flag, and notes format-only coverage for CR and BO. It also clarifies auto-detection for BR/EC and describes the return information: validity, canonical formatting, and entity type.

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?

Front-loaded with the core action, followed by a dense but necessary country list, then the key algorithm exception and return summary. Every sentence and parenthetical contributes to correct invocation; there is no filler.

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 high-complexity tool covering 14 countries and multiple ID schemes, the description covers accepted ID types, check-digit verifiability, exceptions, auto-detection, and result semantics. Since an output schema exists, the lack of exhaustive return-field detail is not a gap; nothing an agent needs to select or call the tool correctly is missing.

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 description coverage is 0% and the schema only defines two plain strings, so the description must add meaning; it does by defining country as ISO 3166-1 alpha-2 codes and mapping each code to accepted tax ID types, including auto-detection for CPF/CNPJ and cédula/RUC. It also ties check-digit behavior to the tax_id parameter.

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 specific verb and resource: 'Validate a Latin American national tax ID, including its check digit.' It also enumerates supported country-specific ID types (CL RUT, AR CUIT/CUIL, MX RFC, etc.), which clearly distinguishes it from sibling validators like validate_phone_number and validate_bank_account.

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 gives clear context for when to use: validating tax IDs of the listed Latin American countries, with auto-detection and format-only caveats. However, it does not explicitly name alternatives or state when-not-to-use it, so it stops short of fully explicit alternative routing.

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