The entire source code for Anthropic’s Claude Code CLI has leaked due to an internal error during a package release. This includes nearly 2,000 TypeScript files and over 512,000 lines of code, exposing the application’s inner workings to competitors and developers. Anthropic has acknowledged the mistake and stated it was not a security breach.

• A packaging error in Claude Code v2.1.88 exposed a source map, leaking the entire ~2,000-file, 512,000+ line TypeScript codebase.
• The leaked code was quickly archived and uploaded to GitHub, gaining tens of thousands of forks within a short time.
• Anthropic says no customer data was exposed and calls it human error, not a security breach, while adding safeguards.
• Developers have already begun reverse-engineering internals, like Claude Code's memory architecture and background memory rewriting system.

Anthropic unintentionally exposed the source code for Claude Code, its AI product, through a public npm package. The leak, which includes sensitive architectural details, poses significant risks for users and gives competitors insights into its technology. Users are advised to take immediate security precautions due to potential vulnerabilities.

• A source map on public npm exposed ~512,000 lines of Claude Code's TypeScript source, discovered by an intern rather than Anthropic itself.
• The leak reveals unreleased internal architecture like "Self-Healing Memory," "Strict Write Discipline," and the always-on "KAIROS" background agent.
• Internal metrics show development problems including a high false claims rate, plus an "Undercover Mode" letting Claude Code contribute to open-source projects without disclosing its identity.
• Users who updated packages around the leak window face added risk from a separate, unrelated malicious attack on the axios package.