Use when the user asks to "design an email A/B test", "set up a multivariate subject/CTA test", "run a send-time test", "build a hold-out group", or "is this email result statistically and practically material?"; produces a falsifiable hypothesis, one-variable-per-cell matrix, sample-size/MDE/duration/power plan, and an effect/uncertainty read from own ESP data.
Install
npx skills add aaron-he-zhu/aaron-marketing-skills --skill send-experiment-designernpx skills add aaron-he-zhu/aaron-marketing-skills --skill send-experiment-designer -a claude-code -gnpx skills add aaron-he-zhu/aaron-marketing-skills --skill send-experiment-designer -a codex -ggemini skills install https://github.com/aaron-he-zhu/aaron-marketing-skills.git --path email/deliver/send-experiment-designergh skill install aaron-he-zhu/aaron-marketing-skills send-experiment-designergit clone --depth 1 https://github.com/aaron-he-zhu/aaron-marketing-skills /tmp/aaron-he-zhu__aaron-marketing-skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/aaron-he-zhu__aaron-marketing-skills/email/deliver/send-experiment-designer ~/.claude/skills/send-experiment-designer # Claude Code
cp -R /tmp/aaron-he-zhu__aaron-marketing-skills/email/deliver/send-experiment-designer ~/.agents/skills/send-experiment-designer # Codex, Cursor, Gemini CLI, Copilot, OpenCode