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

No annotations are present, so the description carries the burden of disclosing behavior. 'Consulta' indicates a read-only lookup, and the optional-date syntax is disclosed, but behavior for omitted or invalid dates, as well as any data-source limits, is not specified.

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 in one sentence and then a compact parameter section. There is no redundant or filler content.

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 simple tool with one optional parameter and an output schema, the description is nearly complete: it states the purpose, the parameter, the accepted formats, and optionality. It does not clarify what happens when fecha is omitted (e.g., whether the current/latest UDIS is returned), which is a small but real 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?

The schema only defines fecha as an optional string/null with no description, so 0% schema coverage means the description must compensate. It does so effectively by specifying the accepted formats (YYYY-MM-DD or DD/MM/YYYY) and explicitly marking the parameter as optional.

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 uses a specific verb ('Consulta') and resource ('valor oficial de las Unidades de Inversión (UDIS) en pesos mexicanos'), making the tool's purpose immediately clear. It is also distinct from the sibling tools because UDIS valuation is a different financial indicator than exchange rates, inflation, interest rates, or reserves.

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 it should be used when an official UDIS value is needed, optionally for a specific date. However, it does not mention any sibling tools or state when an alternative such as consultar_serie_sie would be more appropriate, so usage guidance is only implicit.

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