🛡️ Skill: Harden Pro (v1.0.0)

Executive Summary

harden-pro is the guardian of interface stability. While ui-ux-pro focuses on the "Happy Path", harden-pro builds for Production Reality. This skill focuses on error handling, internationalization (text expansion/RTL), responsive text overflow, and network resilience. A hardened interface never breaks, it gracefully adapts.

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📋 The Resilience Protocol

1. Extreme Input Test: Simulate very long/short text, special characters, and massive datasets.
2. Error Scenario Audit: Map network failures, API timeouts, and validation errors.
3. i18n Validation: Check for text expansion (German/RTL) and logical properties.
4. Empty State Design: Ensure every feature has a teaching empty state.
5. Sanitization: Validate and sanitize all user-facing inputs.

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🛠️ Mandatory Standards (2026)

1. Text Resilience (CSS)

• Rule: Never use fixed width or height for text containers.
• Protocol: Use min-width: 0 for flex/grid items to prevent overflow. Use line-clamp for multi-line truncation and hyphens: auto for long strings.

2. Logical Properties (RTL Support)

• Rule: Avoid left / right / width / height based margins/padding.
• Protocol: Use margin-inline, padding-block, inset-inline-start. This ensures automatic support for Arabic, Hebrew, and other RTL scripts.

3. Graceful Error States

• Rule: No generic "Error occurred" messages.
• Protocol: Every error MUST provide:
  • Clear explanation of what happened.
  • Actionable recovery (Retry/Home button).
  • Friendly tone (Human-grade UX writing).

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🚀 Show, Don't Just Tell (Implementation Patterns)

Resilient Component (React 19)

export function HardenList({ items, isLoading, error, onRetry }) {
  if (isLoading) return <SkeletonList count={5} />;
  
  if (error) return (
    <div className="p-6 border-red-500 bg-red-50 rounded-xl" role="alert">
      <p className="text-red-900 font-medium">Failed to load content.</p>
      <button onClick={onRetry} className="mt-2 text-red-700 underline">Try again</button>
    </div>
  );

  if (items.length === 0) return (
    <div className="flex flex-col items-center p-12 text-center">
      <IllustrationEmpty className="w-32 h-32 opacity-50" />
      <p className="mt-4 text-slate-600">No items found. Create your first one to get started.</p>
    </div>
  );

  return (
    <ul className="grid gap-4">
      {items.map(item => (
        <li key={item.id} className="min-w-0 break-words">
          {item.text}
        </li>
      ))}
    </ul>
  );
}

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🚫 The "Do Not" List (Anti-Patterns)

1. DO NOT assume English-length text. Always test +30% expansion.
2. DO NOT ignore network timeouts. Always implement loading/error boundaries.
3. DO NOT leave actions without feedback (Spinners/Optimistic UI).
4. DO NOT use absolute positioning without considering overflow.
5. DO NOT trust client-side data only.

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📂 Progressive Disclosure

• Impeccable DNA: High-fidelity design standards.
• i18n & Logical Properties: Global-first engineering.
• Error Boundary Patterns: React 19 resilience.