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Generate email subject lines

Use this skill when you need a subject line for any email, want to improve open rates, or are A/B testing subject lines. Generates 5-10 high-converting email subject lines using 100 proven direct-response frameworks organized by psychological trigger (curiosity, urgency, pain point, authority, results, contrarian, value, action, empowerment, story, trend, quick win). Analyzes your email content to match the right frameworks, then outputs subject line variations with preview text recommendations. Trigger on "subject line", "email subject", "what should the subject be", "help with this email subject", "write subject lines", "improve my open rates", "subject line ideas", or any request involving email + subject line.

SKILL.md
name:
email-subject-lines
description:
Use this skill when you need a subject line for any email, want to improve open rates, or are A/B testing subject lines. Generates 5-10 high-converting email subject lines using 100 proven direct-response frameworks organized by psychological trigger (curiosity, urgency, pain point, authority, results, contrarian, value, action, empowerment, story, trend, quick win). Analyzes your email content to match the right frameworks, then outputs subject line variations with preview text recommendations. Trigger on "subject line", "email subject", "what should the subject be", "help with this email subject", "write subject lines", "improve my open rates", "subject line ideas", or any request involving email + subject line.

Generate Email Subject Lines

Generate 5-10 high-converting subject lines for any email using 100 battle-tested frameworks from elite direct-response marketers — matched to your email's specific intent, emotion, and hook.


Why This Works

Subject lines are the most leveraged words you'll ever write. A 10% improvement in open rate on a 10,000-person list means 1,000 more people reading your email — from changing a few words. But most people write subject lines last, when they're tired, using whatever comes to mind first. This skill reverses that by matching your email's intent to proven psychological frameworks that have generated millions in revenue across thousands of campaigns. Every framework is categorized by trigger type so Claude picks the right ones for YOUR specific email.


How to Use This Skill

When triggered, ask the user for:

To generate subject lines, I need:

  1. Paste your email (or describe what it's about)
  2. Email type — Newsletter, promotional, welcome, launch, nurture, announcement?
  3. Audience tone — Casual/friendly, professional, edgy, motivational?
  4. Any words to avoid? — Overused phrases, brand restrictions, etc.

If the user just pastes an email without context, analyze it and generate subject lines immediately.


Process

Step 1: Analyze Email Intent

Read the email content and identify:

  • Primary goal: Sale, engagement, nurture, announcement, content delivery
  • Core emotion: Fear, curiosity, aspiration, frustration, excitement
  • Key hook elements: Numbers, results, pain points, authority figures, timeframes

Step 2: Match Frameworks

Select 3-5 framework categories that align with the email's intent:

Email Intent Best Framework Categories
Sales/promo Urgency, FOMO, Results, Value
Educational Curiosity, Quick Win, Contrarian
Story-based Story, Pain Point, Transformation
Authority-building Authority, Social Proof, Results
Challenge/launch Action, Empowerment, Urgency
Newsletter/content Curiosity, Value, Quick Win, Trend

Step 3: Generate 5-10 Subject Lines

For each, provide:

Subject line: [subject line]
Framework: [which framework it's based on]
Suggested preview text: [preview text that complements the subject line]

Style Rules

  • Keep under 50 characters when possible (mobile optimization)
  • Use specific numbers over vague claims
  • Match the sender's voice (casual vs. professional)
  • Lowercase often outperforms Title Case
  • Questions outperform statements for cold audiences
  • Specificity beats cleverness
  • One clear idea per subject line
  • Emojis: use sparingly, match sender's typical style
  • Avoid: "Unlock," "Discover," "Revolutionary," "Game-changing," "Don't miss"

Preview Text Guidelines

Preview text should:

  • Complement, not repeat the subject line
  • Add specificity or intrigue the subject line lacks
  • Be 40-90 characters (shows fully on mobile)
  • Create a 1-2 punch with the subject line
Subject Line Style Preview Text Approach
Question Answer hint or amplify stakes
Statement Add proof or specificity
Curiosity gap Partial reveal or benefit
Urgency Reinforce deadline or scarcity
Number-based Expand on what's included

Framework Library (100 Frameworks by Trigger)

CURIOSITY TRIGGERS

  • The Is-It-Worth-It Formula: Is [popular tool/habit/strategy] a waste of time?
  • The Pattern Interrupt Question: What does your [mundane thing] say about [you/area]?
  • The Surprising Success Formula: [Impressive result]... without [expected requirement]?
  • The Celebrity Twist Hook: if [famous person] [did unexpected niche thing]
  • The Hidden Knowledge Hook: [Unexpected source] reveals the keys to [desired outcome]
  • The Weird Question Formula: What's the weirdest [niche thing] you've ever [action]?
  • The Earnings Curiosity Hook: How much [desired outcome] should you be [making] in [niche]?
  • The Inside Look Hook: Look inside [new resource] [format]
  • The High-Stakes Question Hook: What makes someone [desirable attribute]?

URGENCY & FOMO TRIGGERS

  • The FOMO Warning Formula: Ignore this and [negative consequence]
  • The Time-Sensitive Check-In: did your [new strategy] already [fail/break]?
  • The Obsolete Method Hook: Why traditional [industry/model] is dead
  • High-Stakes Decision Formula: Quitting on [big accomplishment]
  • Year-Start Preparation Formula: December starts, prepare the [new year] [area] [plan]

PAIN POINT TRIGGERS

  • The Rock Bottom Formula: Dealing with [emotionally vulnerable moment]
  • The Pain Point Reveal Hook: Your [thing] isn't [working]? Here's why
  • The Relatable Struggle Hook: Should I [stick to ideal behavior] or [give up]?
  • The "Invisible Mistake" Hook: The "invisible mistake" [crushing] your [desired outcome]
  • The Hidden Mistake Framework: Are your [common element] killing your [outcome]?
  • The Unspoken Reason Hook: The #1 reason [group] [experience negative situation]
  • Costly Niche Mistake Hook: [Common mistake] is costing you [valuable resource]
  • The "Why Everyone Struggles" Hook: Why so few [audience] get [desired outcome]
  • Common Niche Trap Formula: Why [common approach] fail (even mine)
  • The Wishful Thinking Formula: Still [risky behavior], hoping for the best?
  • Failure Stat Hook: [High number]% of [group] FAIL at [activity] because of this...

AUTHORITY & SOCIAL PROOF TRIGGERS

  • The Authority Name Drop Formula: [Well-known person] [did something with me] - here's what happened
  • The Insider Giveaway Hook: I [invested] [big number] in [authority] — here's everything I learned (for free)
  • The Niche Authority Hook: Learn [skill] from a [tangible credibility] expert
  • The Authority Challenge Hook: Sorry [famous person], but...
  • The Niche Poll Formula: XX [group] told me their biggest problem (do this to fix it)
  • Niche Audit Hook: I reviewed [big number] [assets], most made this critical mistake

RESULTS & SUCCESS TRIGGERS

  • The Short-Term Win Formula: My [X-month] journey to [milestone]
  • The "Instant Results" Formula: "This [tool] [delivered big outcome] in [short time]"
  • The Outlier Success Breakdown: How [thing] achieved [result] in [short timeframe] (not luck)
  • The Growth Snapshot Formula: [Month] [wins]: [number], [bigger number], [bigger number]
  • The Top Performer Breakdown: I tested [X] [tactics] – these [Y] made the most [result]
  • The ROI Revelation Hook: This [increased] my [metric] by [XX]%
  • The First Milestone Formula: How I [achieved] my first [milestone] as a [role]
  • The "Exact Path" Formula: Exactly what to do from [starting point] to [desired result]
  • The High ROI Investment Formula: He [achieved $result] from [low-cost tool]
  • The 10x Multiplier Formula: One change → [Big Result]
  • The Accidental Success Framework: The [$XX] accidental [strategy]

CONTRARIAN & REFRAME TRIGGERS

  • The Positive Reframe Hook: No, [outcome] doesn't have to [negative downside]
  • The "I Was Wrong" Hook: I was wrong about [popular idea]
  • The Dark Side Reveal Formula: The dark side of being [seemingly positive trait] (fixed)
  • The Hidden Cost Formula: The danger of being [seemingly good status]
  • The Unexpected Truth Formula: What if I told you [desired outcome] is not the goal?
  • The Contrarian Advice Formula: Most [topic] advice sucks
  • The "Success Despite" Framework: The [big outcome] built on [contrarian approach]
  • The Not-What-You-Think Formula: Your [thing people blame] may not be the problem
  • What-If Contrarian Strategy: What if [common habit] was the wrong move
  • Contrarian Advice Framework: Don't "[conventional advice]" in [New Year]
  • Paradoxical Success Formula: [Undesirable type] make the best [desirable type]

VALUE & RESOURCE TRIGGERS

  • The "Compressed Value" Formula: My [complex thing] broken down in 1 email
  • The Tangible Freebie Teaser: [Asset Type] [X] steps to [outcome]
  • The "Different Roads To Success" Hook: [number] ways to [achieve] [outcome]
  • The "Perfect Plan" Formula: Inside: Your perfect [resource] for [timeframe]
  • The Irresistible Freebie Formula: FREE [RESOURCE] [emoji]
  • The Niche Success Playbook Hook: The [dream outcome] [resource type]
  • The Anatomy Hook Framework: The anatomy of a [successful system]
  • Niche Playbook Formula: The [New Year] [Niche] Playbook
  • Quick Win Template Formula: This template makes [process] [improvement]
  • Hidden Gem Formula: The best [thing] you've never heard of
  • Timeless Secrets Formula: [Number] timeless secrets to [result]

ACTION & TRANSFORMATION TRIGGERS

  • The Do-This-Now Hook: If you're [archetype], [start] this new [thing]
  • The "Skip The Downside" Hook: [Desirable action] without [typical downside]
  • The "Stop/Start" Formula: Stop being a [current identity] and become a [powerful identity]
  • The Instant Upgrade Hook: [Watch/read] this to [achieve outcome]
  • The "Turn X Into Y" Formula: [X] ways to turn [strategy] into [outcome]
  • The Hate-to-Love Formula: how to stop hating [difficult but necessary thing]
  • The "Do-Or-Die" Hook: How to [result] (if your life depended on it...)
  • The Exit Strategy Framework: Why I quit [popular trend]
  • The Old Way Dilemma: still doing [action] the old way?
  • Yes-You-Can Formula: yes, you can [something unexpected or bold]

EMPOWERMENT & ENCOURAGEMENT TRIGGERS

  • The "Yes, You Can" Formula: Anyone can [achieve outcome] (yes, even you)
  • The Less-Is-More Hook: You don't need [common assumption]. Just [smaller thing].
  • The One Thing Framework: All successful [group] do this ONE single thing
  • The Challenge Acceptance Formula: [Negative situation]? GOOD
  • The Targeted Callout Hook: Only for [specific segment]...
  • The Implied Interest Hook: Because you're interested in [topic]

STORY & EXPERIENCE TRIGGERS

  • The "Miraculous Insight" Hook: [Struggle]—until something clicked.
  • The High-Stakes Failure Formula: My [big number] [topic] f*ck up
  • The Trial & Error Method: [X] [activities] later... [X] essential tips
  • The Love-Hate Formula: My love-hate relationship with [topic]
  • The Big Loss Curiosity Formula: [Big number] [people] [negative result]?
  • Unsuccessful Approach Breakdown: I [studied] one of the worst [subjects] ever

TREND & INNOVATION TRIGGERS

  • The Niche Tech Shift Hook: How [trend] is changing [industry] in [year]
  • The Niche Breakthrough Formula: How [brand] broke [platform] [timeframe]
  • The "Weird Works" Strategy: [X] simple (but weird) [culture] habits to [goal]
  • Unconventional Success Formula: Weird way to [get desirable outcome]

QUICK WIN TRIGGERS

  • The Little-Known Trick Hook: Hi, did you know [little-known hack]?
  • The Fast Win Formula: Quick ([additional benefit]) [niche] secret
  • The Equation Hook: 1 [change] = [better] [outcome]
  • The Quick Challenge Approach: [Short timeframe] [valuable outcome] challenge
  • The "Mini Rant" Hook: Mini rant: Bad ways to [achieve outcome]
  • The Overlooked Factor Hook: Why your [minor factor] matters more than ever
  • The "Facts Over Hype" Hook: The truth about [tactic or technique]
  • The Damn Good Framework: Damn, this is an A+ [advice, resource, thing]
  • The "Insert Here" Strategy: [Insert [common problem] here]
  • Cliche Disruptor Hook: Stop trying to [common advice] please

Quality Criteria

Each subject line must:

  • Be under 50 characters when possible (show fully on mobile)
  • Create a clear reason to open — curiosity, urgency, value, or emotion
  • Match the email's actual content — No clickbait that doesn't deliver
  • Sound human — Like something a real person would text a friend, not a marketing department
  • Be diverse — The batch should use different frameworks, not 5 variations of the same angle

What good looks like

A great batch of subject lines stays under 50 characters wherever possible so every line shows fully on mobile, and each one gives a clear reason to open — curiosity, urgency, value, or emotion. Every line matches the email's actual content; no clickbait that doesn't deliver. The lines sound human, like something a real person would text a friend rather than something from a marketing department, favoring specificity over cleverness with one clear idea per line. And the batch is diverse — different frameworks and psychological angles, not five variations of the same hook — each paired with preview text that complements rather than repeats the subject line.