validate_cpf

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

No annotations provided, so description must disclose behavioral traits. It mentions checking mod-11 digits and rejecting sentinels, but fails to specify return type (boolean/error) or side effects. Important for an agent to know how to interpret the result.

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, front-loaded with imperative 'USE THIS', no wasted words, clearly structured.

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?

Usage context is good, but lack of output schema and return type explanation leaves a gap. For a validation tool, the agent needs to know what the tool returns (e.g., boolean, error message) to act 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?

Schema coverage is 100%. Description adds value beyond schema by clarifying the CPF is exactly 11 digits and that formatting like dots/dashes is ignored.

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?

Description clearly states it validates a Brazilian CPF, specifies the check digit algorithm, and gives the context (KYC/onboarding). It distinguishes from sibling validation tools by naming the specific ID type.

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?

Explicitly tells when to use ('USE THIS to verify a Brazilian CPF before relying on it' and 'Call this for KYC/onboarding of Brazilian individuals'). Lacks explicit 'when not to use' but direction is clear.

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