email-copywriting
Skill9 starsChanged 8 months agoMITView on GitHub
Write effective marketing emails with compelling subject lines, preview text, body copy, and CTAs. Use when writing email campaigns or sequences.
We split this skill into the rules it gives an agent
19 rules. 0 are common, 19 are distinctive, and 0 are very specific to this project.
0
Common
Most of the 3 edited versions we read keep these.
19
Distinctive
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 11
Use this skill when:
- Distinctive: line 22
Before writing email copy, clarify:
- Distinctive: line 33
One email, one goal: If the email has two CTAs pointing to different actions, pick one and remove the other.
- Distinctive: line 34
Subject line > body copy > CTA: If the subject line fails, nothing else matters because no one reads the email.
- Distinctive: line 37
Every sentence must earn the next sentence: If a line doesn't add value, cut it.
- Distinctive: line 95
Create urgency: If the subject line is curiosity-based, the preview text adds urgency
- Distinctive: line 185
Only personalize when it adds genuine value
- Distinctive: line 186
Always set fallback text for missing data ("Hi there" if first name is blank)
- Distinctive: line 187
Don't be creepy — using behavioral data is fine.
- Distinctive: line 188
Test personalized vs non-personalized versions (personalization doesn't always win)
- Distinctive: line 203
If you can say it in fewer words, do
- Distinctive: line 206
Test short vs long versions of the same email — results vary by audience
- Distinctive: line 239
Keep it to 1-2 sentences
- Distinctive: line 241
Don't use P.S. in every email — it loses impact
- Distinctive: line 257
Test ONE variable at a time
- Distinctive: line 259
Run the test for at least 24 hours (preferably 48) before declaring a winner
- Distinctive: line 260
Use open rate for subject line tests, click rate for body/CTA tests, conversion rate for offer tests
- Distinctive: line 261
Document every test and its result — build an institutional testing playbook
- Distinctive: line 300
Before finalizing any email copy:
“Common” is measured: kept by at least 6 in 10 of the 3 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Email Copywriting
When to Activate
Use this skill when:
- Writing subject lines for email campaigns
- Drafting email body copy (promotional, educational, transactional)
- Optimizing CTAs and button copy
- Writing email sequences (welcome, sales, nurture)
- A/B testing email copy elements
- Reviewing and improving existing email copy
- Writing preview text and preheader copy
First Questions
Before writing email copy, clarify:
- What is the email's ONE goal? (Click, reply, purchase, register, read)
- Who is the recipient? (Segment, relationship stage, pain points)
- What action should the reader take after reading?
- What is the offer or value proposition?
- Is this a standalone campaign or part of a sequence? (Context from previous emails?)
- What tone/voice does the brand use? (Formal, conversational, edgy, warm)
- Is this plain text, HTML, or hybrid?
Core Rules
- One email, one goal. If the email has two CTAs pointing to different actions, pick one and remove the other.
- Subject line > body copy > CTA. If the subject line fails, nothing else matters because no one reads the email.
- Write for scanners. Most people scan emails in 3-8 seconds. Structure for scanning with headers, bold text, short paragraphs, and bullet points.
- Write like a human, not a brand. Emails that feel like letters from a person outperform corporate announcements.
- Every sentence must earn the next sentence. If a line doesn't add value, cut it.
- Mobile first. 60%+ of email opens are on mobile. Short subject lines, short paragraphs, large tappable buttons.
- The CTA must be unmissable. One primary CTA, above the fold, clear and action-oriented.
Subject Line Formulas
Curiosity-Driven
- "The [thing] that [unexpected result]"
- "Why [common practice] doesn't work anymore"
- "I was wrong about [topic]"
- "[First name], you're not going to believe this"
- "The secret behind [impressive result]"
Benefit-Driven
- "How to [achieve result] in [timeframe]"
- "[Number] ways to [solve problem] (without [common objection])"
- "The fastest way to [desired outcome]"
- "Get [specific result] — here's how"
- "Your [problem] ends today"
Urgency/Scarcity
- "[X] hours left: [offer summary]"
- "Last chance for [specific benefit]"
- "This closes tonight at midnight"
- "Only [number] spots left"
- "[First name], your [offer] expires soon"
Social Proof
- "How [customer name] achieved [result]"
- "Join [number] people who [action]"
- "The [thing] [industry leaders] swear by"
- "What [respected person/company] taught me about [topic]"
Personal/Conversational
- "Quick question, [first name]"
- "Can I be honest with you?"
- "I made a mistake"
- "This is for you (literally)"
- "You'll thank me later"
Subject Line Rules
- Length: 30-50 characters (6-10 words). Under 40 characters performs best on mobile.
- Front-load the compelling part. What's after character 40 gets truncated on mobile.
- Avoid spam triggers: FREE, ACT NOW, !!!, ALL CAPS, $$$
- Use personalization selectively. [First name] in subject lines increases open rates ~5-10% but loses impact if overused.
- Lowercase can work. All-lowercase subject lines feel casual and personal: "hey, quick thought about your strategy"
- Questions outperform statements (in most cases)
- Numbers outperform words: "5 ways" beats "five ways"
- Emojis: One emoji can lift opens 2-5% in B2C. Avoid in B2B. Never more than one.
Preview Text Optimization
Preview text (preheader) is the text that appears after the subject line in the inbox. It's your second chance to earn the open.
Best Practices
- Length: 40-90 characters (complements, doesn't repeat, the subject line)
- Extend the story: Subject line starts a thought, preview text continues it
- Add context: What will the reader get from opening?
- Create urgency: If the subject line is curiosity-based, the preview text adds urgency
- Avoid default text: "View this email in your browser" or the first line of the email body
Preview Text Formula
Subject: [Curiosity or benefit hook]
Preview: [Context, additional benefit, or urgency that complements the subject]Examples:
Subject: "The pricing mistake costing you customers"
Preview: "I see this in 90% of the businesses I audit."
Subject: "Your weekly marketing roundup"
Preview: "This week: a LinkedIn hack that tripled our reach."
Subject: "Last day: 30% off everything"
Preview: "Sale ends tonight at 11:59 PM. Here's what to grab."Email Structure
The Inverted Pyramid
The most effective email structure narrows from broad to specific:
[ATTENTION] — Broad hook that connects to the reader's world
|
[INTEREST] — Narrow to the specific topic/value
|
[DESIRE] — Build the case for action (benefits, proof, urgency)
|
[ACTION] — Single, clear CTA buttonOne-Column Layout
- One column is the only reliable layout for mobile
- Maximum width: 600px for the email body
- Font size: 16px minimum for body text, 22-28px for headings
- Line height: 1.5 for readability
- Paragraph length: 1-3 sentences maximum
Structural Elements
- Opening line — Hook or connection to the reader's situation (1-2 sentences)
- Value body — The main content, broken into scannable chunks (3-5 short paragraphs or bullets)
- Transition to CTA — Bridge the value to the action ("Here's how to apply this...")
- CTA button — Single, clear, action-oriented button
- P.S. line — Optional but highly effective (see below)
CTA Button Copy
Rules for CTA Buttons
- Action verb + benefit: "Get My Free Guide" not "Submit"
- First person often wins: "Start My Trial" outperforms "Start Your Trial"
- Specific over vague: "Download the 2025 Report" beats "Learn More"
- One primary CTA per email. Secondary links are fine in text, but one button dominates.
- Above the fold. The CTA should be visible without scrolling on mobile.
- Repeat the CTA at the bottom of longer emails.
CTA Copy Examples
| Weak | Strong |
| Submit | Get My Free Checklist |
| Click Here | See the Results |
| Learn More | Show Me How It Works |
| Buy Now | Start Saving Today |
| Sign Up | Join 5,000+ Marketers |
| Download | Grab Your Copy |
Button Design
- Minimum size: 44x44 px tap target (mobile-friendly)
- High contrast color (stands out from the email background)
- Rounded corners (tested to outperform sharp corners in many contexts)
- Whitespace above and below the button (breathing room)
Personalization Techniques
Beyond First Name
| Technique | Example | Data Required |
| Recent behavior | "I noticed you checked out [product]..." | Page visit tracking |
| Purchase history | "Since you loved [Product A], you'll love..." | Purchase data |
| Location | "Marketing events near [city] this month" | Location data |
| Company/role | "As a [job title] at [company]..." | CRM data |
| Engagement | "You've been reading a lot about [topic]..." | Email click data |
| Milestone | "Congratulations on your 1-year anniversary with us!" | Date tracking |
| Conditional content | Show different offers based on segment | Segment tags |
Personalization Rules
- Only personalize when it adds genuine value
- Always set fallback text for missing data ("Hi there" if first name is blank)
- Don't be creepy — using behavioral data is fine; making it feel like surveillance is not
- Test personalized vs non-personalized versions (personalization doesn't always win)
Email Length by Purpose
| Email Type | Ideal Length | Reasoning |
| Promotional | 50-125 words | Quick hit, fast action |
| Newsletter | 200-500 words | Curated value, scannable |
| Educational | 300-600 words | Teaching requires depth |
| Sales email | 150-300 words | Clear problem-solution-CTA |
| Welcome email | 100-200 words | Warm, brief, set expectations |
| Re-engagement | 50-100 words | Short, direct, low friction |
| Transactional | As needed | Clarity over brevity |
Length Rules
- If you can say it in fewer words, do
- Long emails work ONLY when every word earns its place
- Break long emails into scannable sections (bolded headers, bullets, short paragraphs)
- Test short vs long versions of the same email — results vary by audience
Plain Text vs HTML
When to Use Plain Text
- Personal outreach (sales emails, founder emails)
- Reply-based campaigns ("Hit reply and tell me...")
- High-deliverability contexts (plain text has fewer spam filter triggers)
- 1:1 communication style
- B2B relationship-building emails
When to Use HTML
- Product showcases (images are essential)
- Newsletters with branded design
- Promotional campaigns with visual CTAs
- E-commerce (product images, pricing, buttons)
- Any email where design supports comprehension
Hybrid Approach
Many marketers use "designed plain text" — HTML emails with minimal formatting that look like personal emails but have branded fonts, a logo, and styled CTA buttons. This combines the personal feel of plain text with the functionality of HTML.
The P.S. Line Technique
The P.S. line is one of the most-read elements of any email. Eye-tracking studies show readers often scan: subject line, first line, and P.S. before reading the body.
Uses for P.S.
- Reinforce the CTA: "P.S. The early-bird price ends Friday. [Link]"
- Add social proof: "P.S. 2,300 people have already signed up."
- Create urgency: "P.S. Only 12 spots remaining."
- Add a personal touch: "P.S. I wrote this while my daughter was napping. True story."
- Introduce a secondary offer: "P.S. If this isn't for you, forward this to someone who needs it."
P.S. Rules
- Keep it to 1-2 sentences
- Include a link if it references an action
- Don't use P.S. in every email — it loses impact
- Make it feel like an afterthought (even though it's strategic)
A/B Testing Email Copy Elements
What to Test (In Priority Order)
- Subject lines — Highest impact on opens
- CTA copy and placement — Highest impact on clicks
- Email length — Short vs long versions
- Tone/voice — Formal vs casual
- Personalization — With vs without
- Send time — Morning vs afternoon, weekday vs weekend
- From name — Person vs brand name
- Preview text — Different angles
Testing Rules
- Test ONE variable at a time
- Minimum 1,000 recipients per variant (500 per group minimum)
- Run the test for at least 24 hours (preferably 48) before declaring a winner
- Use open rate for subject line tests, click rate for body/CTA tests, conversion rate for offer tests
- Document every test and its result — build an institutional testing playbook
- Statistical significance matters: aim for 95% confidence before acting on results
Testing Documentation Template
TEST: [What's being tested]
DATE: [Send date]
SAMPLE SIZE: [Total and per variant]
VARIANT A: [Description]
VARIANT B: [Description]
METRIC: [What's being measured]
RESULT: [Variant A: X% | Variant B: Y%]
WINNER: [A or B]
CONFIDENCE: [Statistical significance %]
INSIGHT: [What did we learn?]
NEXT TEST: [What will we test next based on this?]Email Copywriting Checklist
Before Sending
- Is there ONE clear goal for this email?
- Is the subject line under 50 characters and compelling?
- Does the preview text complement (not repeat) the subject line?
- Is the opening line a hook, not a generic greeting?
- Is the email scannable? (Short paragraphs, headers, bullets)
- Is there ONE primary CTA that is unmissable?
- Is the CTA above the fold on mobile?
- Is the CTA button copy action-oriented and specific?
- Is the email mobile-friendly? (One column, 16px+ font, tappable buttons)
- Are personalization merge tags tested with fallbacks?
- Is the tone consistent with the brand voice?
- Has the email been proofread by a second pair of eyes?
- Is the unsubscribe link present and functional?
- Has the email been tested on Gmail, Outlook, and Apple Mail?
- Would YOU open and read this email if it arrived in your inbox?
Quality Gate
Before finalizing any email copy:
- Can you state the email's goal in one sentence?
- Does the subject line create enough curiosity or promise enough value to earn an open?
- Does the first line earn the second line?
- Is every sentence necessary? (Cut anything that doesn't serve the goal)
- Is the CTA crystal clear?
- Has the copy been read aloud? (Catches awkward phrasing and robotic tone)
- Is the email appropriate for the recipient's relationship stage? (Don't hard-sell a new subscriber)
- Has at least one subject line A/B test been planned?
Other versions3 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 3
- chunkydotdev/email-skills★ 5same name
- Ken-Technology/cold-email-skills★ 4same name
- email-marketing-skills/email-marketing-skills★ 1same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository73 other files it gives its agents.
- AGENTS.mdAGENTS.md
- CLAUDE.mdCLAUDE.md
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- The first 60 shown.
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