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

With no annotations, the description must carry the full behavioral burden. It discloses key traits: default currencies, behavior without date (last close), and restriction to business days. However, it omits whether results are read-only, return format, pagination, rate limits, or error handling, leaving gaps for a tool with no annotation support.

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 with the core purpose and key details, followed by parameter-related information and temporal behavior. It is appropriately sized for the tool's complexity, though the long currency list could be seen as slightly dense, but it is necessary given the lack of schema documentation.

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?

Given no annotations, no output schema, and 0% schema coverage, the description covers essential aspects like default currencies and date behavior. However, it lacks information about return values, error cases, or authentication needs, leaving it incomplete for a tool that must rely solely on the description for behavioral guidance.

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. It provides detailed semantics for the 'monedas' parameter by listing all valid currency codes, but it does not explain the 'fecha' parameter's format beyond what the schema pattern implies, nor does it clarify that 'fecha' expects YYYY-MM-DD. Still, the currency enumeration adds significant meaning.

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 resource: 'Cotizaciones oficiales del BCU en pesos uruguayos (compra/venta)', clearly identifying official BCU exchange rates. It distinguishes itself from siblings like uy_ui (which likely handles UI only) by listing multiple currencies. However, it doesn't explicitly contrast with siblings like ar_feriados or cuota, leaving some ambiguity about scope.

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 implies usage through examples ('Default USD, EUR, ARS, BRL') and temporal behavior ('Sin fecha: último cierre publicado. Solo días hábiles'), but it does not explicitly state when to use this tool versus alternatives or mention prerequisites. The context is implied rather than spelled out.

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