validate_nif_pt

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

Discloses mod-11 check digit validation. No annotations present, so description carries burden. Could mention it is read-only/idempotent, but sufficient for a simple 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 with no fluff: first sentence gives action and context, second adds algorithm and sibling reference. Information is front-loaded and efficient.

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?

Covers purpose, usage context, algorithm, and sibling differentiation. Lacks explicit return value description, but reasonable given typical validation tool behavior and no output schema.

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 already describes parameter well (100% coverage). Description adds purpose and algorithm context beyond schema, aiding interpretation.

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?

Uses 'verify' verb with specific resource 'Portuguese NIF', explicitly distinguishes from sibling 'validate_dni' for Spanish tax ID. Clear and 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?

States exactly when to use ('before invoicing or onboarding'), warns not to assume 9 digits valid, and provides explicit alternative for Spanish tax ID.

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