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

With no annotations, the description carries the full burden and does add real domain context: the index exists every day including weekends and is published roughly one month ahead, which is critical to knowing which dates are valid. It stops short of stating return format or error behavior for out-of-range dates.

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 clauses, front-loaded with the resource definition, followed by availability behavior and the default. No filler sentences.

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?

No output schema and no annotations, so the description must stand alone; it covers availability, publishing horizon, and the optional-date default well. It leaves the returned value's format and behavior for dates outside the published window unspecified, a minor remaining gap.

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% and the single parameter has only a regex pattern, so the description must compensate; it does so by naming the parameter's meaning (a date) and defining the default when omitted (today). The expected YYYY-MM-DD shape is left to the schema pattern rather than restated, which is acceptable.

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 resource and verb-like retrieval ("Valor de la Unidad Indexada (UI) del BCU para una fecha"), which is immediately distinguishable from siblings like uy_cotizaciones. It does not, however, explicitly distinguish itself from uy_ui_historico, which an agent may reasonably confuse with a single-date lookup.

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?

Usage is implied by the note "Sin fecha: hoy", which tells the agent the parameter is optional and what the default is. There is no explicit guidance on when to prefer this tool over uy_ui_historico for historical queries, so the agent must infer the boundary.

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