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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the 'sin efectos secundarios / solo lectura' sentence mostly restates them. The description does add genuinely new behavioral facts: determinism and concrete limits (1 s per call, up to 1 MB result). Minor inconsistency: it says input is capped at 64 KB while the schema's maxLength is 1048576, which could mislead.

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 bilingual duplication doubles length, but each language block is front-loaded with the verb, then when/not-for, then side effects and limits — no wasted sentences within a block.

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 an output schema present and rich annotations, the description covers purpose, alternatives, safety and limits adequately. The only gap is the unreconciled 64 KB vs schema maxLength of 1 MB, which an agent could read as contradictory input constraints.

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 100%, so both `data` and `input_encoding` are already documented. The description adds nothing about the utf8/hex/base64 encoding choice, which is the one non-obvious parameter decision — baseline 3 applies.

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 ('Calcula el hash FNV-1a de 64 bits, no criptográfico') and immediately distinguishes it from the closest sibling by name. An agent can select it against the many other checksum-* tools without opening any 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 names the use cases (error detection, sharding, hash tables) and an explicit 'No para' clause routes the agent to checksum-fnv1a32 when 32-bit output is wanted. Both the positive and negative conditions are stated, not inferred.

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