Use when reviewing security-sensitive web apps, SharedArrayBuffer usage, worker-heavy apps, editors, or measurement features that require cross-origin isolation. Check both headers and real browser behavior.
Install
npx skills add thedaviddias/Front-End-Checklist --skill cross-origin-isolationnpx skills add thedaviddias/Front-End-Checklist --skill cross-origin-isolation -a claude-code -gnpx skills add thedaviddias/Front-End-Checklist --skill cross-origin-isolation -a codex -ggemini skills install https://github.com/thedaviddias/Front-End-Checklist.git --path skills/cross-origin-isolationgh skill install thedaviddias/Front-End-Checklist cross-origin-isolationgit clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist /tmp/thedaviddias__Front-End-Checklist
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/thedaviddias__Front-End-Checklist/skills/cross-origin-isolation ~/.claude/skills/cross-origin-isolation # Claude Code
cp -R /tmp/thedaviddias__Front-End-Checklist/skills/cross-origin-isolation ~/.agents/skills/cross-origin-isolation # Codex, Cursor, Gemini CLI, Copilot, OpenCode