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

Annotations already declare readOnlyHint=true, openWorldHint=false, idempotentHint=true and destructiveHint=false, so the 'no side effects / deterministic' lines are largely redundant. However, the description adds genuinely new operational context: the 64 KB input cap, 1 s per-call budget and 1 MB result cap, plus the fact that the response reports whether text changed. Minor inconsistency: it says 64 KB input while the schema allows 262144 characters.

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 and front-loaded, with labeled sections (When / Not for / Side effects / Deterministic / Limits). But the entire content is duplicated in Spanish and English, roughly doubling length without adding information for a given reader.

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 shape need not be explained, and the tool is a simple two-parameter read-only operation. With alternatives, limits, determinism and side effects all covered, an agent has everything needed to call it correctly.

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% and the enum plus default are already documented in the schema, so baseline 3 applies. The description names the four forms but adds no semantics about what each form does (canonical vs compatibility, composed vs decomposed) that would help an agent pick one.

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 ('Applies Unicode normalization form NFC, NFD, NFKC or NFKD') and adds the observable outcome ('reports whether the text changed'). It also explicitly differentiates from the nearest sibling, remove-accents, so the agent can choose 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?

Uses explicit 'When:' and 'Not for:' sections, naming the excluded case (stripping combining diacritical marks) and the sibling tool that handles it. The positive condition (exact transform/compare/measure rather than approximation) is concrete enough to act on.

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