Anthropic Accidentally Open-Sourced Claude Code. Here's What No One Is Talking About.

On March 31, 2026, someone at Anthropic forgot to add *.map to .npmignore. That single oversight shipped a 59.8 MB source map inside the @anthropic-ai/claude-code v2.1.88 npm package, exposing 512,000 lines of unobfuscated TypeScript across 1,906 files. The entire internal architecture of their flagship AI coding agent, out in the open. Anthropic filed DMCA takedowns. GitHub repos started disappearing. Then a developer in South Korea woke up at 4 a.m., rewrote the core architecture from scratch in Python and Rust, and pushed it to GitHub. The repo hit 50K stars in 2 hours and 100K in 24 hours, the fastest-growing repository in GitHub history. Most coverage focused on the drama: the leak, the takedowns, the legal battle. But the actual code reveals things Anthropic clearly never intended anyone to see. What actually leaked Not the model weights. Not customer data. Not the training pipeline. What leaked is the agent harness: the orchestration layer that turns a language model into a codi