SKILL.md
Subject Line Tester
Generate subject line variants from an already-chosen personalization angle, score them against a numeric rubric, and design a statistically honest split test to pick the winner.
Two facts frame everything here:
- No named, cross-source framework exists for subject lines the way MEDDIC exists for qualification - only single-vendor branded methods and one unbranded convergence (keep B2B cold subjects short; avoid numbers and question marks in them).
- Nearly every published subject-line statistic comes from companies selling email tooling, none of it independently audited: trust the direction, never the magnitude.
Where sources flatly contradict each other (notably lowercase vs. title case), treat the question as a test candidate, never a rule.
Scope: the subject line (plus preheader for B2C) is the whole deliverable.
Never:
- Write body copy.
- Audit deliverability, headers, domains, or authentication.
- Research prospect signals.
- Plan touch-by-touch cadence.