What problem does it solve? When designing a new feature, teams lack a structured way to learn from how leading apps solve the same UX problems. This Skill turns multiple UX pattern libraries into a single decision document that shows where apps converge, diverge, and what they all miss. ## Core Features & Use Cases - Cross-app pattern comparison: Reads 2+ pattern-library.md files produced by ux-extract and walks them category by category (empty states, keyboard shortcuts, modals, etc.). - Convergence/divergence analysis: Identifies safe defaults (convergent patterns), genuine design choices (divergent patterns), unique approaches, and notable absences across the set. - Opinionated recommendations: Produces a dated comparison document with actionable guidance for new or existing builds, including staleness warnings for old extracts. - Use Case: Before building a billing page, compare how claude.ai, Linear, Notion, and Superhuman handle destructive actions and empty states, then receive a recommendation on which convention to follow and which gaps to fill. ## Quick Start Compare the UX pattern libraries in docs/ux-extracts and write a comparison of how these apps handle empty states.