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

With no annotations, the description carries the full burden and does disclose key traits: dates are inclusive, weekends and holidays are discounted, and negative `sumar` subtracts. It omits edge behaviors such as what happens when `hasta` is absent in count mode or when both modes' params are supplied.

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, front-loaded with the primary count behavior and then the `sumar` variant. Every clause adds information with no redundancy.

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 4-param computation tool with no output schema and no annotations, the description covers both operating modes and all parameter meanings. It could be more complete by noting the differing return type per mode (a count vs a date) or error handling, but nothing essential to calling it correctly is missing.

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%, so the description must compensate, and it does: `pais` maps to Uruguay/Argentina, `desde` is the anchor date, `hasta` is the implied second date, and `sumar` is N business days with negative values subtracting. Formats and the enum itself are left to the schema, but the semantics of all four params are covered.

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 precise computed resource (business days between two dates for UY/AR) and a second mode (add N business days) selected by `sumar`. This clearly separates it from siblings like ar_feriados/uy_feriados, which list holidays rather than compute business-day counts.

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 description distinguishes the two usage modes via `sumar` (omit it to count, include it to add/subtract), which tells the agent when to reach for each behavior. It doesn't cite alternative sibling tools or exclusions, so it stops short of full routing guidance.

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