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

Annotations already declare readOnlyHint, openWorldHint=false, idempotentHint and destructiveHint=false, so 'solo lectura, sin red' largely repeats structured data. The description still earns credit for adding operational limits (64 KB input, 1 s per call, 1 MB result) and explicit determinism, which are not in the annotations.

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?

The description is front-loaded correctly, opening with what the tool does, but it is bilingual and ends with a dangling pointer ('full EN: inputSchema.description') that adds no value. The 'Cuándo' block enumerates unrelated Colombian rules, padding the definition with content that does not help select this tool.

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?

With an output schema present and rich annotations, the description need not explain return values, and it covers purpose, exclusion, determinism and limits. The only gap is the lack of any note on what the 18-entry result looks like or ordering, though the output schema likely covers that.

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?

There is a single parameter with 100% schema description coverage, including min 1984, max 2200 and an example, so the schema carries the semantics. The description only restates that the output is for a given year and does not add format or edge-case detail beyond the schema. Baseline 3 applies.

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 and resource: lists the 18 Colombian national holidays for a year, applying Ley Emiliani and Easter-based rules. It also names the sibling it is not (co-is-holiday), so an agent can distinguish the two without opening either schema.

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?

The 'No para' clause explicitly excludes the per-date check and points to co-is-holiday, which is exactly the routing information an agent needs. However, the 'Cuándo' clause lists broader topics (COP amounts, IVA, GMF, UVT) that this tool does not actually compute, which introduces mild misdirection even though the exclusion sentence limits the damage.

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