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

No annotations exist, so the description carries the full burden. It usefully discloses the official data source and the bounded set of supported years, but says nothing about return format, ordering, caching, or how filtered results behave when no holiday matches.

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 no filler, front-loading the resource and its scope. The available-years constraint follows immediately, so the most actionable detail appears early.

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 3-param lookup tool with no output schema or annotations, it covers source, year range, and type vocabulary. The omission of mes semantics and any description of the returned holiday records leaves gaps an agent must infer.

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 for all three parameters. It clarifies anio (years 2025/2026) and restates the tipo enum values, but the mes parameter is never mentioned and no format/semantics are given beyond the schema's numeric bounds.

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/resource: national Argentine holidays by year, sourced from the official argentina.gob.ar site. It is clearly distinguishable in intent from sibling ar_feriado_proximo (next holiday), though it never names that 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?

It discloses hard usage constraints — only years 2025 and 2026 are available — which tells the agent when the call will succeed. However, it gives no explicit when-to-use/when-not guidance or routing to the 'proximo' sibling for upcoming-holiday queries.

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