Anthropic accidentally leaked Claude Code's source code. Here's what that means.

Last week, someone noticed that version 2.1.88 of the Claude Code npm package was 60MB heavier than it should have been. Inside: reconstructable source code for Claude Code's CLI. Around 512,000 lines of TypeScript across nearly 2,000 files. Significant portions of the agent codebase that Anthropic had kept private, exposed by a single build mistake. How does a mistake like this even happen? When developers ship software, they often minify the code first. That means compressing it into an unreadable blob of abbreviated variable names and stripped formatting. The goal is smaller files, faster downloads, and some protection from competitors reading your work. To debug that minified code, teams use source maps: files that translate the ugly compressed version back into the original readable code. These are internal tools. They should never ship to users. This one did. What was actually inside? Reported findings include: How Claude Code's agent loop works Multi-agent coordination logic Aro