Cotización del BCU de un día

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

Annotations already cover read-only, idempotent, non-destructive and open-world traits. The description adds genuinely new behavior: the no-publication rule for non-business days, the 7-day lookback cap, and the fact that the response reports which date was actually used. It stops short of stating what happens when no prior business day falls inside the window.

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 blocks, front-loaded with the core purpose, then the currency list, then the edge-case rule. Every sentence adds information an agent needs; nothing is restated from the schema or annotations.

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, return-value structure need not be described, and the description still notes that the response reports the date used. All three parameters are explained, and the main non-obvious failure mode (weekend/holiday) is documented.

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 carry the load and it does: it spells out the date format (AAAA-MM-DD), expands each currency enum value (dólar billete, Unidad Indexada, peso argentino billete, real billete), and defines hacia_atras's exact fallback semantics and limit.

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: the official BCU exchange rate for a given date, in Uruguayan pesos, and enumerates the supported currencies. The single-date scope implicitly separates it from cotizacion_mensual, but the sibling is never named, so differentiation is inferential rather than explicit.

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?

Gives concrete operational context: weekends and holidays have no publication, and hacia_atras=true falls back to the previous business day within a 7-day window. It does not say when to prefer this tool over cotizacion_mensual or what to do if no publication exists within the window.

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