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onewave-ai avatar

Email Subject Line Optimizer

onewave-ai/claude-skills
264 installs244 stars
Summary

If you're sending marketing emails or newsletters, this gives you multiple subject line variations using established copywriting frameworks and estimates open rates based on historical patterns. You paste in your email context, and it generates A/B test candidates with predictions on which will perform better. The format is clean with copy-paste ready options and explanations for why each approach might work. Honestly most useful if you're doing regular sends and want to move faster than manually brainstorming five versions of the same hook. Saves the back-and-forth of "does this sound too salesy" conversations.

Install to Claude Code

npx -y skills add onewave-ai/claude-skills --skill email-subject-line-optimizer --agent claude-code

Installs into .claude/skills of the current project.

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belt - the only tool your agent needs
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belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
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inference shell
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CodeRabbit
CodeRabbit
AI writes the code. CodeRabbit catches the slop.
Try For Free →
MCP-ready Email SendingMCP-ready Email Sending
MCP-ready Email Sending
Plug Mailtrap into your AI workflow and let it handle the email.
Connect Mailtrap MCP →
Make your agent a DeFi expert
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Agent, run crypto. Access onchain data & trade routes via 1inch.
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Capacitor - Shared memory for your team’s coding agents.
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CodeScene MCP ServerCodeScene MCP Server
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belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
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Files
SKILL.mdView on GitHub

Email Subject Line Optimizer

A/B test subject line variations using proven copywriting frameworks. Predict open rates based on historical performance.

Instructions

You are an expert at email marketing and copywriting. Create high-performing subject lines, predict open rates, and provide A/B testing recommendations.

Output Format

# Email Subject Line Optimizer Output

**Generated**: {timestamp}

---

## Results

[Your formatted output here]

---

## Recommendations

[Actionable next steps]

Best Practices

  1. Be Specific: Focus on concrete, actionable outputs
  2. Use Templates: Provide copy-paste ready formats
  3. Include Examples: Show real-world usage
  4. Add Context: Explain why recommendations matter
  5. Stay Current: Use latest best practices for marketing

Common Use Cases

Trigger Phrases:

  • "Help me with [use case]"
  • "Generate [output type]"
  • "Create [deliverable]"

Example Request:

"[Sample user request here]"

Response Approach:

  1. Understand user's context and goals
  2. Generate comprehensive output
  3. Provide actionable recommendations
  4. Include examples and templates
  5. Suggest next steps

Remember: Focus on delivering value quickly and clearly!

Featured
CodeRabbit
CodeRabbit
AI writes the code. CodeRabbit catches the slop.
Try For Free →
MCP-ready Email SendingMCP-ready Email Sending
MCP-ready Email Sending
Plug Mailtrap into your AI workflow and let it handle the email.
Connect Mailtrap MCP →
Make your agent a DeFi expert
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Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →
Capacitor - Shared memory for your team’s coding agents.
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Make coding agent sessions - Searchable, Shareable, Vendor-neutral & Scored.
Try For Free →
CodeScene MCP ServerCodeScene MCP Server
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Your agent targets a perfect 10 Code Health score. Deterministic. Every commit.
Try For Free →
Give your AI the whole web as clean markdownGive your AI the whole web as clean markdown
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Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →
belt - the only tool your agent needs
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belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
one prompt install →
inference shell
inference shell
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Categories
Testing & QADebuggingMarketing & SEO
First SeenJun 3, 2026
View on GitHub

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