Anthropic Accidentally Leaked Claude Code's Full Source

Anthropic accidentally shipped Claude Code's entire source code in their public npm package — not a hack, just a bad build config. Bun's bundler generates .map files by default, and a missing .npmignore entry left them in the published package. Those map files pointed to an R2 bucket with 1,900 TypeScript files and 512,000+ lines of unobfuscated code.

Inside: ~40 permission-gated tools, ~50 slash commands, multi-agent orchestration internals, and unreleased features including something called "Kairos mode" and "Undercover Mode". Mirror repos appeared within hours and collectively pulled thousands of stars before Anthropic quietly pushed a patched npm version and delisted the old ones. No DMCA, no public statement.

Why it matters: The real story isn't the leak — it's what's inside. Unreleased modes and the full agentic architecture are now public, giving competitors and researchers a detailed look at how Anthropic builds its flagship coding agent.