Anthropic Leaks 512,000 Lines of Claude AI Code in Major Blunder

Anthropic accidentally published a 59.8 MB source map to the public npm registry on 31 March 2026, exposing roughly 512,000 lines of internal code for Claude Code (a product generating ~$2.5B/year) and revealing internal projects and model codenames; the leak was quickly copied across the internet. The report also warns of a separate incident during the same update window where users who updated via npm between 00:21 and 03:20 UTC may have received a Trojan, and Anthropic recommends using the official Native Installer to mitigate risk.