Anthropic Leaked Product PLAYBOOK: How to 100x Your Coding
An intern found 59.8MB of Anthropic's internal source code on npm at 4am. Buried inside: the exact system they use to run Claude. Here's how to replicate it.
On the night of March 31, 2026, Chaofan Shou was doing what interns do at 4am when they probably should be sleeping: poking around npm packages.
Buried in the release was a .map file he found out 512,000 lines of TypeScript.
He posted about it on X at 4:23am. By breakfast, the codebase had been mirrored across GitHub by hundreds of developers.
Anthropic confirmed the leak was real. A packaging error, they said, not a security breach.
The code turned out to reveal something far more interesting: the system that let Anthropic ship a new Claude feature almost every day last year.
It’s kind of insane.
For this newsletter, we went through Claude’s code end to end
and extracted every technique startups should be copying right now.
Inside you will find:
How Anthropic Actually Writes a Prompt
Why Everything You Paste Into Claude Gets Forgotten
How to Give Claude Memory That Survives Every New Conversation
Why You Should Never Solve a Complex Problem in One Chat
How to Write a CLAUDE.md That Actually Works (Updated)
Bonus: What Karumi (YC F25) Found in the Leaked Claude Code Source
Before we get into it, a quick heads up: in 5 days we’re updating our pricing.
If you’ve been thinking about upgrading to premium, now is the moment, current subscribers lock in today’s rate forever.
After next week, new subscribers will pay significantly more.
No tricks, just a real deadline.
The reason? We are working on 100xing the value of product market fit.
You are going to love what’s coming next 🔥
💭 Remember!
As a premium subscriber you’ll also get access to all the other Claude resources we put together, such as:
4️⃣ 🚨 The Ultimate AI Fundraising Copilot (Built With Claude)
1️⃣2️⃣ How I Rebuilt My SEO Strategy Inside Claude (The Playbook)
We’re already 70,000+ founders and operators inside!
