5 cold email patterns that actually get replies (from generating 500+ sequences)

I've been deep in the cold email trenches building an AI sequence generator, and after analyzing hundreds of outputs and real-world feedback, here's what I keep seeing separate the emails that get replies from the ones that get archived:

1. Your first line isn't about you — ever. The biggest killer is opening with "I'm [name] from [company]." Nobody cares yet. Lead with something about them — a recent hire, a podcast appearance, a product launch. Earn the next sentence.

2. Shorter > longer. Always. Emails under 75 words consistently outperform 150+ word ones. Not sometimes — basically always. If you can't say it in 3-4 sentences, you don't know what you're asking for yet.

3. The follow-up sequence matters more than the first email. Most people obsess over email #1 and then send a lazy "just bumping this" for email #2. Your Day 3 and Day 7 follow-ups should each bring new value or a new angle. Same ask, different reason to care.

4. Spam filters detect AI patterns now. If you're using AI to write emails (and you should be), know this: filters are catching structural patterns — identical sentence lengths, em-dash overuse, formulaic CTAs. Vary your structure. Mix short punchy lines with longer ones. Sound human, not templated.

5. One CTA. One. "Would love to hop on a call, or feel free to check out our site, or reply with your thoughts" — that's three asks and zero clarity. Pick one action. Make it easy. "Worth a 15-min chat Thursday?" Done.

I built these lessons into a free tool called 99 Agents — it generates full 4-email sequences with timing built in. But honestly, even if you're writing manually, these five things will move the needle.

What's working for you all on cold outreach right now? Curious what patterns others are seeing.