Investigate slow WinUI 3 layout, scrolling and virtualization using native ETW captures, timed operation trees and managed GC suspension context. Use bounded queries for runtime performance questions, not crash analysis or UI correctness.
Install
npx skills add microsoft/winappCli --skill winapp-performancenpx skills add microsoft/winappCli --skill winapp-performance -a claude-code -gnpx skills add microsoft/winappCli --skill winapp-performance -a codex -ggemini skills install https://github.com/microsoft/winappCli.git --path plugins/winapp/skills/winapp-performancegh skill install microsoft/winappCli winapp-performancegit clone --depth 1 https://github.com/microsoft/winappCli /tmp/microsoft__winappCli
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/microsoft__winappCli/plugins/winapp/skills/winapp-performance ~/.claude/skills/winapp-performance # Claude Code
cp -R /tmp/microsoft__winappCli/plugins/winapp/skills/winapp-performance ~/.agents/skills/winapp-performance # Codex, Cursor, Gemini CLI, Copilot, OpenCode