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

With no annotations, the description carries the full behavioral burden, and 'Respuesta mínima' is the only disclosure — it hints the response is a terse yes/no rather than a detailed holiday record. It does not state whether the check covers national vs regional holidays, how weekends are treated, or any rate/permission constraints, which is a gap for a zero-annotation 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?

Three short sentences with zero filler, front-loaded with purpose, then the default-date behavior, then the response shape. Nothing redundant or padded.

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 two-parameter yes/no query with no output schema and no annotations, the description covers purpose, country scope, default date, and response brevity. The main remaining gap is routing guidance against the many holiday-related siblings, but the core call is unambiguous.

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 0% for two parameters, so the description must compensate. It does clarify that pais means Uruguay or Argentina and that fecha defaults to today when omitted, but it never explains the 'uy'/'ar' code values, the required YYYY-MM-DD format, or why pais is required while fecha is not — partial compensation only.

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?

States a specific verb+resource ('dice si una fecha es feriado o día hábil') and scope ('en Uruguay o Argentina'), which is enough for an agent to know it answers a yes/no holiday question rather than listing holidays like the sibling ar_feriados/uy_feriados. It does not name those siblings explicitly, so the differentiation is implicit rather than stated.

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 one useful usage cue: 'Sin fecha: hoy' tells the agent the date is optional and defaults to today. However, it never says when to prefer this tool over the country-specific siblings (ar_feriados, uy_feriados, dias_habiles) or ar_feriado_proximo/uy_feriado_proximo, leaving the alternative-selection decision to inference.

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