Anthropic Claude Code Source Code Leaked: What Happened, Why It Matters, and What Comes Next

On March 31, 2026 Anthropic accidentally published Claude Code's full source via a 59.8 MB source map in an npm release.

The exposed source map contained about 512,000 lines of unobfuscated TypeScript across ~1,900 files and was mirrored on GitHub within hours.

Anthropic began filing takedown notices as third-party repositories, including a popular claw-code mirror/rewrite, gained rapid traction.