
Claude Code Source Leak: The Chain Reaction Caused by One .npmignore Mistake
On March 31, 2026, the AI world received an unexpected “April Fools’ Eve gift”: the full source code of Anthropic’s star product, Claude Code, accidentally made its way onto the internet because of a packaging mistake. This was not a hack. It was not an insider leak. Someone simply forgot to add *.map to .npmignore. Just like that, 510,000 lines of TypeScript, 44 hidden feature flags, and a mysterious background autonomous agent called KAIROS were exposed to everyone within hours. ...



