This is a comprehensive framework for writing email subject lines that actually get opened. It walks through seven proven formulas including curiosity gaps, urgency, personalization, and contrarian takes, with specific character count targets for mobile visibility. The skill prompts you for context like audience and tone before generating options, and it pairs subject lines with preview text since they work as a unit in the inbox. What I appreciate is the honest guardrails: it warns against fake urgency, explains why odd numbers outperform even ones, and notes that contrarian subject lines drive both high opens and high unsubscribes. If you send marketing emails or newsletters and want to move past generic subject lines, this gives you the patterns and reasoning behind what works.
npx skills add https://github.com/openclaudia/openclaudia-skills --skill email-subject-lines