Subject line variants with stated rationale

Use when you have the email written and need options to test rather than one line you are guessing at.

subject-line-variants-with-rationale.md

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You are an email copywriter. Write 12 subject lines for the email below.

Email body: {{EMAIL_BODY}}
Audience: {{AUDIENCE}}
What the reader gets by opening: {{READER_PAYOFF}}
Sender name shown in inbox: {{FROM_NAME}}

Output a table: Subject line | Character count | Angle used | Why this could beat the others | Risk if it underperforms

Cover at least these angles, one each: direct benefit, specific number from the body, curiosity gap, question, news or change, objection named, plain internal-sounding line, deadline or timing.

Constraints:
- Maximum 55 characters unless the angle needs more, and flag any line over 55.
- No emoji. No all caps words. No "Re:" or "Fwd:" fakery. No false urgency for something with no real deadline.
- Every line must be honest about what is inside. If the body does not support the claim, do not write the line.
- Do not use "unlock", "supercharge", "game changer", "must read" or exclamation marks.

Then pick the two you would test first and say in one sentence each what a win would tell me about this audience.

Fill in before running

Replace each placeholder with your own detail. The more specific you are, the less the model invents.

{{EMAIL_BODY}}
{{AUDIENCE}}
{{READER_PAYOFF}}
{{FROM_NAME}}

Getting a better result

Paste the whole body. Subject lines written from a topic summary promise things the email does not deliver.
Test two lines with genuinely different angles, not two rewordings of the same idea, or the result teaches you nothing.
Check the character counts yourself. Models miscount, and mobile clients cut around 35 to 45 characters.

Questions about this prompt

When do I need twelve options rather than writing the line myself?

When the send is big enough that a test result means something and you want to learn what this audience responds to. For a note to two hundred people, write the line. Twelve options with stated angles are worth the time when the finding outlives the send.

What has to be ready before I ask for variants?

The finished body pasted whole, the audience, what the reader gets by opening, and the from name that will show in the inbox. Subject lines written from a topic summary promise things the email never delivers. The from name matters because the same line reads differently over a person than over a brand.

What does the table give me beyond twelve lines?

Character counts, the angle used, why each could win and the risk if it does not, then the two the model would test first with what a win would tell you. The angle column is the working part, because it stops you testing two rewordings of one idea and calling it an experiment.

What should I not take on trust?

The character counts. Models miscount, and mobile clients cut somewhere around 35 to 45 characters, so check the numbers and read each line truncated. The other trap is picking two finalists that share an angle, which produces a winner that teaches you nothing about the audience.