Prompt Details
Model
(claude-5-sonnet)
Token size
932
Example input
[NEWSLETTER NAME AND TOPIC]: Growth Notes — actionable marketing tactics for early-stage founders
[TARGET SUBSCRIBER AND THEIR GOAL]: Early-stage founders who want one actionable growth idea they can implement this week
[SUBJECT LINE, PREVIEW TEXT, AND FULL ISSUE BODY]: Subject: How to grow faster | Preview: This week's growth tip | Body: Welcome to this week's issue of Growth Notes. This week we're talking about referral programs. 400-word explanation of what referral programs are, why they work, a generic Dropbox example, CTA to reply with questions.
[CURRENT OPEN RATE AND CLICK RATE]: 34% open rate | 1.2% click rate
[GOAL OF THIS ISSUE]: Educate subscribers and grow reply rate
Example output
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EMAIL NEWSLETTER AUDITOR v1.0
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NEWSLETTER: Growth Notes — marketing tactics for early-stage founders
SUBSCRIBER: Early-stage founders wanting actionable growth ideas for this week
GOAL: Educate and grow reply rate
OVERALL ISSUE SCORE
█████████████░░░░░░░
Score: 67/100
READABLE — Opens well but losing readers before the end
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SECTION SCORES
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Subject Line █████░░░░░ 10/20 "How to grow faster" matches 10,000 other inbox emails
Preview Text ████░░░░░░ 8/20 "This week's growth tip" adds zero information
Hook and Opening ██████░░░░ 12/20 "Welcome to this week's issue" is the newsletter version of "hey guys"
Body and Value █████████░ 17/20 Once past the opener the content is solid and specific
CTA and Sign-off ██████░░░░ 10/20 "Reply with questions" has no compelling prompt to make someone reply
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OPEN RATE KILLERS (Fix Before Next Send)
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SUBJECT LINE IS INVISIBLE IN AN INBOX
Problem: "How to grow faster" is so generic it triggers the reader's mental skip response. Every growth newsletter, business book, and LinkedIn post promises this. Your 34% open rate says your list is warm — but this subject line is performing despite itself, not because of itself.
Fix: Get specific to this issue's actual content: "The referral program that grew Dropbox from 100K to 4M users in 15 months" — name a real example in the subject line and let curiosity do the work.
Impact if fixed: Very High
PREVIEW TEXT WASTES THE SECOND SUBJECT LINE
Problem: "This week's growth tip" in the preview text is a missed opportunity. After the subject line, preview text is the second-most important open driver. Yours kills the momentum instead of building it.
Fix: Use preview text to extend the hook: "Most founders skip this step. Here's exactly how to set it up in an afternoon."
Impact if fixed: High
WELCOME BACK OPENER KILLS MOMENTUM
Problem: "Welcome to this week's issue of Growth Notes" is pure friction. The reader already knows what newsletter this is — they opened it. Starting with a pleasantry before delivering value signals nothing important is happening yet.
Fix: Open directly on the most interesting sentence in the issue: "Dropbox grew from 100,000 users to 4 million in 15 months. They did not spend a dollar on ads. Here is the exact mechanic they used."
Impact if fixed: High
NO COMPELLING REPLY PROMPT
Problem: "Reply with any questions" is the weakest possible CTA for a newsletter trying to grow reply rate. It is conditional, open-ended, and gives no specific reason to respond.
Fix: Replace with a specific prompt and a personal offer: "Reply and tell me — do you have a referral program? I will tell you what I would change."
Impact if fixed: Medium
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SUBJECT LINE REWRITES
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Angle: The Specific Example
Subject line: The referral trick that grew Dropbox 40x without paid ads
Preview text: Most founders set this up wrong. Here's the version that actually works.
Why this works: Naming a recognizable company with a specific result creates proof before the open — readers open to verify the claim
Angle: The Counterintuitive
Subject line: Stop asking for referrals. Do this instead.
Preview text: The difference between referral programs that grow and ones that get ignored.
Why this works: Contradiction to received wisdom creates a curiosity gap that only the open can resolve
Angle: The Direct Outcome
Subject line: Add a referral loop to your product this week
Preview text: Took Dropbox 15 months to scale. Takes you an afternoon to set up.
Why this works: Specific time commitment (an afternoon) lowers the perceived barrier — founders open because they think they can actually do this
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HOOK REWRITE
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REWRITTEN HOOK:
"Dropbox had 100,000 users. They wanted 4 million.
They did not hire a growth team. They did not run ads. They added one mechanic to their product that gave users a reason to invite people — and a reason to accept the invite.
15 months later: 4 million users.
That mechanic is a referral loop. Here is the version that works for early-stage products, why most founders build it wrong, and how to set up the right version this afternoon."
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A/B TEST IDEAS
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Test 1: Subject line specificity
Control: "How to grow faster"
Variant: "The referral trick that grew Dropbox 40x without paid ads"
Hypothesis: Named company with specific result outperforms generic growth promise for skeptical founders
Metric: Open rate
Priority: High
Test 2: Preview text as subject line extension
Control: "This week's growth tip"
Variant: "Most founders set this up wrong. Here's the version that actually works."
Hypothesis: Preview text that extends the hook increases opens from readers who scan both fields before deciding
Metric: Open rate
Priority: High
Test 3: Opening line — welcome vs. direct
Control: "Welcome to this week's issue of Growth Notes."
Variant: "Dropbox grew from 100,000 users to 4 million in 15 months without spending a dollar on ads."
Hypothesis: Opening directly on the most interesting sentence retains more readers past the first line
Metric: Click rate
Priority: High
Test 4: Reply CTA specificity
Control: "Reply with any questions"
Variant: "Reply and tell me: do you have a referral program? I will tell you what I would fix."
Hypothesis: Specific prompt with a personal offer generates significantly more replies than an open-ended invitation
Metric: Reply rate
Priority: Medium
Test 5: Send day
Control: Current send schedule
Variant: Test Tuesday 8am vs Thursday 8am
Hypothesis: Founders check email earlier in the week when planning — Thursday may compete with end-of-week noise
Metric: Open rate
Priority: Low
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AUDIT COMPLETE — Email Newsletter Auditor v1.0
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CLAUDE-5-SONNET
Most newsletters lose readers not because the content is bad — but because the subject line never got opened, the hook never earned the scroll, or the issue had no clear reason to exist. This Claude prompt audits any newsletter issue and delivers: an overall score (0–100), subject line and open rate analysis, hook and retention breakdown, the exact lines losing readers mid-issue, a complete rewrite of your weakest section, and 5 A/B tests to run next send. Works for Substack, Beehiiv, ConvertKit
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Updated 3 weeks ago
