Claude Code Source Leak Details

Claude Code Source Leak Details | Generated by AI

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Question: How to see that Claude Code source leaked?

Answer: The source code for Anthropic’s Claude Code (the official CLI tool) was reportedly leaked on March 31, 2026. The leak originated from an exposed .map (source map) file in the @anthropic-ai/claude-code package on the npm registry.

While the original repository you linked (instructkr/claude-code) is described as a Python feature port and workspace inspired by the leak, the actual leak details and evidence can be found by looking for the following indicators:

1. The Source of the Leak (npm)

The leak was discovered by security researcher Chaofan Shou (@Fried_rice). He identified a cli.js.map file (approximately 60MB) in the official npm package. This source map contained references to the original, unobfuscated TypeScript source code, which was then mirrored across various GitHub repositories.

2. Evidence within the Leaked Code

The leaked codebase (estimated at ~512,000 lines of code) contains several “unhinged” and unreleased features that confirm its authenticity as internal Anthropic code:

“Buddy” System: A hidden Tamagotchi-style pet system inside the terminal that hatches an ASCII companion (like a duck, capybara, or dragon) based on your user ID.
Undercover Mode: A feature that automatically hides AI traces (like Co-Authored-By lines) when Anthropic employees contribute to public repositories.
Internal Codenames: The code refers to the project as “Tengu” and mentions future model versions like “Fennec” (Opus 4.7) and “Sonnet 4.8”.
“Dream” System: A background process that triggers every 24 hours to “consolidate” and tidy up session memories.

3. Repository Structure

The leaked src/ directory typically includes:

src/tools/: Implementation of tools like BashTool, FileEditTool, and YOLO classifier (an automated permission system).
src/commands/: Slash commands like /commit, /review, and /compact.
src/bridge/: A communication layer for IDE extensions (VS Code/JetBrains).

References:

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