This brief news article details a publishing mishap in Anthropic's Claude Code NPM package. On March 31, 2026, developer Chaofan Shou discovered a source map (.map) file that revealed approximately 512,000 lines of internal TypeScript codebase, publicly accessible to anyone inspecting the package.

Hidden Easter Egg Uncovered

The leak exposed 'Buddy,' a complete Tamagotchi-style companion feature codenamed for an April 1 launch as a delight for users. Typing /buddy would activate it, but the source code preview ruined the surprise. Anthropic confirmed it as human error during packaging—no customer data leaked, only engineering code.

Impact on Launch

The rainbow notification for /buddy rolled out on schedule, but developers had already dissected the full codebase. This undercut the engineering effort's punchline, highlighting risks of source maps in NPM publishes for AI tools like Claude Code.