LeadHaste
BeginnerNo variables to fill — paste & go

Audit and rank your subject lines before you hit send

Puts every subject line candidate through a brutal pre-send audit: a 1-10 plausibility score, its biggest weakness named, spam-pattern flags, and a fixed rewrite. You get a ranked list with a clear verdict — two to test, the rest to kill — instead of sending on gut feel.

The prompt
You are a cold email reviewer who has audited subject lines across millions of sends and can spot a doomed one before it burns a domain. You judge by one standard: would a busy executive, scanning their inbox for two seconds, read this as a plausible human email — or as outreach to be deleted?

I'm going to paste a list of subject lines I'm considering. For each one:

1. Score it 1-10 for inbox plausibility.
2. Name its biggest weakness in one blunt sentence — spam pattern, vagueness, clickbait smell, marketing tone, or overfamiliarity.
3. Note any words or patterns that commonly trip spam filters or prospect skepticism.
4. Offer one rewritten version that keeps the intent but fixes the weakness.

Then rank the full list best to worst and tell me which two to A/B test and which to kill outright. Do not be polite about it — a diplomatic audit is a useless audit. If every line I gave you is weak, say so and propose three of your own based on my campaign context.

Before you audit anything, interview me. Ask me these questions ONE AT A TIME, waiting for my answer each time:
1. Paste your subject line candidates, one per line.
2. What does the email body say — paste it or give me the two-sentence version.
3. Who's the audience, and how senior are they?
4. Are these going out cold, or to a warm or triggered list?

Once you have my answers, run the audit. Keep the whole thing scannable — scores, sentences, and the final ranking.

How to use it

  1. 1

    Copy the prompt into Claude, ChatGPT, or any LLM.

  2. 2

    Paste every candidate you're considering — including ones you suspect are weak; the audit is cheapest before sending.

  3. 3

    Read the weakness sentences carefully; they teach you more than the scores.

  4. 4

    Test the top two picks in your sequencer and bring the results back next session to recalibrate.

Best practices

  • Audit before every campaign launch, not just when something underperforms — bad subjects also feed spam-filter reputation.

  • If a line scores 8+ but feels wrong for your market, trust your market knowledge and say so; the model will re-rank with that context.

  • Include your control subject line in the list so new candidates are ranked against a known baseline.

  • Run the rewrites back through the audit; second-pass versions often outscore the originals.

Example: what this looks like in practice

An SDR manager at a staffing firm collects seven subject line candidates from her team for a campaign targeting HR directors. She pastes them with the email body. The audit scores 'Revolutionize your hiring process!' a 2 with the note 'reads as a marketing blast and revolutionize is a filter magnet', while 'contract roles in Q4' scores 8. Two lines get killed, one rewrite ('your hiring backlog' from 'Help with hiring?') outranks its original, and the team A/B tests the top two. The winning line holds a 71% open rate across the quarter and becomes the campaign control.

Best fit

Roles
SDR / BDRSales LeaderFounder / CEOMarketer
Company size
Solo founderStartup (1–10)SMB (11–50)Mid-market (51–500)
Audience
B2B
Industries
Any industry
Works with
Any LLM
Difficulty
Beginner

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Prompt FAQ

Frequently asked questions

Watch for known trigger patterns: urgency words, money claims, 'free', 'guarantee', excessive punctuation, and all-caps. But modern filtering is behavioral too — engagement history and sending patterns matter as much as words. This audit flags the lexical risks per line, which is the part you can fix before sending; pair it with proper warmup for the rest.