The ~34-line body is lean — tight Quick Reference bullets and short Check/Fix/Explain/Code Review directives — and offloads detail to references; the single motivating intro sentence is brief enough to earn its place rather than the padded level-2 case.

Gives concrete, specific guidance — "Find all places... where a count value is concatenated with a string or where only singular/plural branching is used" and "Replace... with Intl.PluralRules-based key selection or ICU MessageFormat plural syntax" — naming exact patterns to find and fix; per the instruction-only scoring note, the absence of inline code is not penalized since the guidance is actionable.

Presents a clear, unambiguous review workflow (Quick Reference → Check → Fix → Explain → Code Review) where the Code Review section acts as the verification pass; for this single-purpose review skill the simple-skills note supports a top score, and it is not a destructive/batch operation that the cap-at-2 rule targets.

The body is a well-organized overview that signals a single one-level-deep reference — "see references/rule.md" — for full implementation details, and that file exists, matching the clear-overview-with-well-signaled-reference anchor rather than the inline-bloated or under-signaled lower levels.

Lists multiple concrete review actions — "reviewing string concatenation involving counts", "translation key lookups", and "i18n library configurations" — plus the explicit goal of checking plural forms, matching the "lists multiple specific concrete actions" anchor rather than the partial level 2.

Opens with an explicit "Use when reviewing..." trigger (the when) and states the what — "to check whether plural forms are handled correctly for all target locales" — clearly answering both what and when, which the level-2 anchor only half-satisfies.

Uses natural developer vocabulary a user would say when hitting this problem — "string concatenation", "counts", "translation key lookups", "i18n library configurations", "plural forms", "target locales" — giving good coverage rather than the sparse level-2 set.

Occupies a clear niche (i18n plural handling) with distinct triggers around count concatenation and plural forms, making it unlikely to fire for an unrelated skill; not the generic, overlapping level-2 case.