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

No annotations are provided, so the description carries the full behavioral burden. It does disclose two useful traits: the boundary is inclusive ('a partir de una fecha (inclusive)') and the default is today when no date is given. It says nothing about timezone, what happens when no upcoming holiday exists, or the response shape, leaving meaningful gaps for an unannotated 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 tight sentences with the core purpose front-loaded and the default behavior appended; nothing is wasted. It is close to optimally concise, though the trailing 'y días restantes' is slightly ambiguous about whether it refers to input or output.

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?

Complexity is low (one optional parameter), but with no output schema and no annotations the description should say more about what is returned. 'Días restantes' hints at output content but is ambiguous, and return format/default-when-none remain unstated.

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%, so the description must compensate. It explains the single parameter's meaning ('a partir de una fecha') and that the boundary is inclusive, plus the default (today). It does not restate the YYYY-MM-DD format, but the schema's regex pattern already covers that.

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 states a specific verb and resource: retrieve the next Argentine national holiday. 'Próximo' scopes it against the broader sibling ar_feriados (which presumably lists all), so an agent can distinguish the two. It stops short of naming the sibling explicitly.

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?

'Sin fecha: hoy' clarifies the behavior when the optional parameter is omitted, giving implied usage guidance. However, there is no explicit when-to-use-this-vs-ar_feriados routing statement, only the implicit 'próximo' scoping.

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