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

Goes beyond the annotations (readOnlyHint, idempotentHint, openWorldHint) by stating no network access, no stored state, determinism, and concrete limits (64 KB input, 1 s per call, 1 MB result). These are operational constraints the annotations cannot express.

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 front-loaded with labeled sections (Cuándo, No para, Efectos, Límites) that scan quickly. The full ES/EN duplication roughly doubles length without adding information, which is the only real cost.

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 not be described. Purpose, exclusions, side effects, determinism, and hard limits are all covered — 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%, so the baseline is 3; the description earns extra by explaining that ñ normally strips to n and that keep_enye preserves ñ/Ñ 'for Spanish', which adds intent beyond the schema's terse 'Keep ñ and Ñ'. The text param gets no extra guidance beyond the example already in the schema.

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?

Names a specific verb and resource (strip diacritics from text) and illustrates with concrete transformations (á→a, ü→u, ñ→n). The optional ñ behavior is stated up front, so an agent knows exactly what the tool produces.

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?

Has explicit 'Cuándo' and 'No para' sections that name the sibling alternative unicode-normalize and the exact condition that selects it (normalization form NFC/NFD/NFKC/NFKD and reporting whether text changed). No inference required.

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