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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered; the description still adds determinism and concrete limits (64 KB input, 1 s per call, 1 MB output). Minor inconsistency: the schema allows maxLength 1 MB for the input while the description caps input at 64 KB, which could confuse an agent on large payloads.

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?

Front-loaded with the core action, then cleanly segmented into when/not-for/side-effects/limits. The full Spanish and English duplication roughly doubles the length, which is a deliberate bilingual choice but dilutes density.

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?

An output schema exists so return values need no explanation, and the description supplies limits, determinism and side-effect guarantees. The only gap is the input-size figure conflicting with the schema's maxLength, leaving the true ceiling ambiguous.

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 indent enum values, defaults and sort_keys semantics are already documented. The description restates the indent options and key sorting but adds no format or edge-case detail beyond the schema, so the 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 (parse and re-serialize JSON with indentation, optional key sorting) and explicitly contrasts with the sibling json-minify. An agent can distinguish it from json-sort-keys, json-canonicalize and json-minify 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' section names the triggering conditions (transform, compare, check structured data) and a 'No para' section names the alternative tool (json-minify) for the opposite operation. Both when-to-use and when-not-to-use are covered.

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