| name | subject-line-optimizer |
| description | Improve newsletter open rates through better subject lines. Use when: (1) Writing subject lines for tacosdedatos editions, (2) Analyzing why an edition had low open rates, (3) A/B testing subject line variants, (4) Reviewing subject lines before sending. Produces 5-10 variants with recommendations. |
Subject Line Optimizer
Improve tacosdedatos open rates (currently 28-33%, target 40%+).
Context: /agents/shared/tacosdedatos-growth-playbook.md for performance data.
Proven Patterns at tacosdedatos
| Pattern | Example | Performance |
|---|---|---|
| Question | "¿Nos conocemos?" | High |
| Contrarian | "A lo mejor esto de la IA sí vale la pena" | 31.84% |
| Specific/Technical | "Un minutito: Anatomía de una timestamp" | 31.78% |
| Personal | "Lo Que Ando Haciendo" | 31.4% |
| Direct benefit | "Busca lo más vital, no más" | 33.52% (best) |
Quick Formulas
Question: ¿[Surprising question about pain point]?
Contrarian: [Challenge common belief]
Specific: [Number] [things] para [benefit]
Personal: [Personal action]: [topic]
Benefit: [Achieve X] en [time/effort]
Generation Process
- Identify core value: What's the ONE thing readers get?
- Generate 5-10 variants across different patterns
- Check constraints:
- Under 50 characters (critical info in first 35)
- Natural Spanish (not Spain-only)
- Creates curiosity
- Matches tacosdedatos voice
- Recommend top 3 with reasoning
What to Avoid
✗ "Newsletter #47" → No value proposition
✗ "INCREÍBLE TUTORIAL" → Spammy caps
✗ "¡¡¡No te lo pierdas!!!" → Desperate punctuation
✗ "¡Mola!" → Spain Spanish
✗ Over 60 characters → Gets cut off
Output Format
# Subject Lines: [Edition Topic]
**Core value**: [One sentence]
## Top Picks
1. **"[Subject]"** (X chars)
Why: [Reasoning]
2. **"[Subject]"** (X chars)
Why: [Reasoning]
3. **"[Subject]"** (X chars)
Why: [Reasoning]
## All Variants
| Pattern | Subject | Chars |
|---------|---------|-------|
| Question | ... | X |
| Contrarian | ... | X |
| etc. | ... | X |