validar_identificacion_fiscal

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

With no annotations, the description carries the full behavioral burden. It discloses that the check covers both format and check digit and is inherently a non-mutating verification, which is useful. It does not state the return value (e.g., boolean vs. error message), how malformed input is surfaced, or whether it rejects empty strings, so key operational behavior is left implicit.

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?

One front-loaded sentence with zero filler. Every clause earns its place by naming the operation, the identifier types, and the two validation dimensions.

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 simple single-parameter validation tool the description covers the essential purpose, but there is no output schema and no annotations, so return semantics should have been stated and are not. An agent knows what to send but not what to expect back.

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 single 'identificacion' parameter has no schema-level description, so the description must compensate. It usefully identifies the accepted input domain (NIF, NIE, CIF), but adds no format guidance (spaces, hyphens, casing, length) to help construct a valid value.

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 gives a specific verb ('Comprueba si') and a precise resource set (NIF, NIE, CIF) plus the exact validation scope (formato y dígito de control). It is unambiguous about what the tool checks, but it never differentiates itself from the sibling tools, so it falls short of a 5.

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?

Usage is implied by the validation semantics: an agent can infer it should call this when it needs to verify a Spanish tax identifier. However, there is no explicit when-to-use statement, no mention of when not to use it, and no pointer to any alternative among the siblings.

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