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

Annotations already declare readOnly, idempotent and closed-world, yet the description still adds real value: no network, no stored state, determinism, and concrete limits (64 KB input, 1 s per call, 1 MB result). The accepted-format leniency (braces, urn:uuid: prefix, missing hyphens) is behavioral detail unavailable anywhere else.

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?

Content is labeled and front-loaded with the core action, and every labeled block carries distinct information. The parallel Spanish/English duplication doubles length, which is defensible for locale coverage but is still redundancy.

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?

With one parameter, an output schema, and full annotations, the description covers purpose, alternative routing, determinism, and operational limits. Nothing an agent needs to call this correctly is missing.

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 100% for the single 'uuid' parameter, so the schema carries the formal contract. The description still contributes format acceptance rules that an agent cannot infer from the schema, though it does not say what happens on malformed input.

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 ('valida un UUID e informa versión, variante y la marca de tiempo') and scopes it precisely to v1/v6/v7 timestamp extraction. Sibling tools like uuid-v4, uuid-v7 and ulid-decode are clearly differentiated by capability rather than name overlap.

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?

Uses explicit 'Cuándo' / 'No para' framing and names the excluded alternative (ulid-decode) with its reason. Minor blemish: the 'when' clause says 'an identifier has to be generated in this format', which nudges toward a generation use case this tool does not serve, while uuid-v4/uuid-v7 siblings do.

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