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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety restatement adds little. The description does add real context beyond the annotations: determinism (same input, same output) and concrete limits (64 KB JSON input, 1 s per call, 1 MB result), which are not in the annotations or schema.

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?

Well structured with explicit labels (Cuándo / No para / Efectos / Límites), but the whole content is duplicated in Spanish and English, roughly doubling length for a single calling agent. Front-loading is good, but the doubled text is padding relative to a single-locale consumer.

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, output-schema-backed, fully annotated tool, the description covers everything needed: input notation, what it is not, safety profile, determinism and hard limits. Nothing material 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 'morse' parameter, so the baseline is 3. The description goes further by defining the expected input notation (dots/dashes, letters separated by spaces, words by / or 3+ spaces), which is the main way a caller can get this wrong.

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+resource ('Decodifica código Morse internacional') and immediately defines the input alphabet (dots/dashes, spaces between letters, / or 3+ spaces between words). It explicitly names the opposite tool (morse-encode), so the agent can distinguish it from the sibling without opening either 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?

Explicit 'Cuándo' clause with the condition (convert bytes/text to or from this encoding exactly, without guessing) and an explicit 'No para' clause naming the alternative morse-encode. Both when-to-use and when-not-to-use are present.

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