It's called andrej-karpathy-skills. Worth saying up front: it's not actually from Karpathy. Someone took his public rants about where LLMs fall over when they write code and turned them into a single CLAUDE.md you drop into any project. That's the whole repo. One file. 178k stars. The reason it's blowing up is the four rules it gives Claude:
1. Think before coding. Surface your assumptions first instead of charging in.
2. Simplicity first. No speculative features, no "while I'm here" extras.
3. Surgical changes. Touch only what the task needs, leave the rest alone.
4. Goal-driven execution. Give Claude the success criteria and let it loop until it hits them, instead of dictating every step.
That last one is the bit most people sleep on. You stop micromanaging the steps and start describing what "done" looks like. Claude is genuinely good at looping toward a target. It's worse at following a 12-step recipe you wrote.
Drop the file in, restart Claude Code, and you'll feel the difference on the next task.
Have a read and tell me which of the four your projects break most often. Mine's number 2.