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 a critical limitation — it explicitly says it does NOT query DGI and does NOT confirm existence or vigencia, preventing an agent from over-trusting the result. It stops short of describing the return value shape (no output schema exists), so the transparency is useful but not complete.

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 short sentences, the capability is front-loaded and the limitation follows immediately. No filler.

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 one-parameter validator with no annotations and no output schema, the description covers scope and the key negative guarantee, but leaves real gaps: the exact accepted input format and what the tool returns on success or failure.

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% — the single 'rut' parameter has no description, only min/max length. The description partially compensates by stating the expected format (12 digits), but this conflicts with the schema's maxLength of 32, leaving the accepted input format (separators, hyphens) ambiguous.

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 and resource plus the exact scope: validates format and check digit of a Uruguayan RUT. No sibling in the list (feriados, cotizaciones, ui) does anything comparable, so no differentiation is needed.

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 (call it to validate a RUT) but there is no explicit when-to-use, when-not-to-use, or named alternative. The scope disclaimer 'no consulta a DGI' borders on guidance but describes behavior rather than when to pick this tool.

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