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

The readOnlyHint annotation already communicates that this is a safe read-style operation. The description adds the supported units and categories, which is useful context, but it doesn't disclose details such as precision, rounding, or how strictly unit strings are matched. For a pure converter, this gap is moderate.

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 main action and scope are front-loaded, and the lengthy remainder is a single necessary inventory of units. There is no filler or repetition, and each part of the description earns its place.

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?

All four required parameters are already documented in the schema, and the description supplies the full domain vocabulary. There is no output schema, so describing the result format would have been an improvement, but that is a minor omission for an otherwise simple conversion tool.

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 describes each parameter at a high level, but the description is the only place that enumerates valid unit codes per category (e.g., m, km, kg, C, m2, ms, Pa, J, N, W). This materially helps an agent supply correct values for unidadOrigen and unidadDestino, going well beyond the schema's few examples.

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 leads with a specific verb and resource: 'Convierte entre unidades de medida' and then enumerates 12 concrete categories, which clearly separates it from the sibling converters and calculators. An agent can identify the tool's purpose without inspecting the schema.

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 scope is explicit: use this tool for unit conversions across the listed categories, and those categories implicitly exclude sibling tools like convertir_edad_mascota. It does not name alternative tools or state when-not-to-use conditions, but the category inventory gives clear contextual guidance.

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