Inside Claude Code: 12 Hidden Features Anthropic Didn't Want You to See

On March 31, 2026, security researcher Chaofan Shou discovered something remarkable in the npm registry: Anthropic had shipped Claude Code v2.1.88 with a 60MB source map still attached. That single .map file contained 1,906 source files and 510,000 lines of fully readable TypeScript. No minification. No obfuscation. Just the raw codebase, sitting in a public registry for anyone to download. Within hours, mirror repositories appeared on GitHub. One hit 50,000 stars in two hours — the fastest any repository has reached that milestone. Anthropic pulled the package, but the code was already everywhere. The irony? The root cause was a known bug in Bun (oven-sh/bun#28001), the JavaScript runtime that Anthropic acquired at the end of 2025. Their own toolchain leaked their own product. We spent the last 24 hours reading the source. Here are the 12 most interesting things hiding in it. 1. KAIROS — Claude Never Sleeps The biggest reveal is KAIROS: an always-on daemon mode where Claude Code runs