claudecode

Claude Code — Rebuilt from Leaked Source

On March 31, 2026, the full source code of Anthropic's Claude Code CLI was leaked via a .map file exposed in their npm registry. This repo contains that source rebuilt into a runnable CLI.

Quick Start

Prerequisites: Bun v1.1+

git clone https://github.com/fazxes/claude-code.git
cd claude-code
bun install
bun run build
bun dist/cli.js

That's it. The CLI will launch and prompt you to authenticate via OAuth (same flow as the official Claude Code).

Commands

bun dist/cli.js                    # Launch interactive REPL
bun dist/cli.js --help             # Show all options
bun dist/cli.js --version          # Show version
bun dist/cli.js -p "your prompt"   # Non-interactive mode (pipe-friendly)
bun dist/cli.js auth login         # Authenticate

How It Was Leaked

Chaofan Shou (@Fried_rice) discovered the leak:

"Claude code source code has been leaked via a map file in their npm registry!"

— @Fried_rice, March 31, 2026

The source map in the published npm package contained a reference to the full, unobfuscated TypeScript source, downloadable as a zip from Anthropic's R2 storage bucket.

What's Inside

• ~1,900 source files, 512,000+ lines of TypeScript
• Runtime: Bun
• Terminal UI: React + custom forked Ink
• CLI parser: Commander.js
• Layout engine: Pure TypeScript port of Yoga (Meta's flexbox engine)

Architecture

src/
├── main.tsx                 # Entrypoint (Commander.js CLI parser)
├── commands.ts              # Command registry
├── tools.ts                 # Tool registry (~40 tools)
├── QueryEngine.ts           # LLM query engine (Anthropic API)
├── context.ts               # System/user context collection
├── ink/                     # Custom Ink fork (terminal React renderer)
├── commands/                # Slash command implementations
├── tools/                   # Agent tool implementations
├── components/              # React UI components
├── services/                # API, MCP, OAuth, telemetry
├── screens/                 # Full-screen UIs (REPL, Doctor)
├── native-ts/               # Pure TS ports of native modules
│   ├── yoga-layout/         # Flexbox layout engine
│   ├── color-diff/          # Syntax-highlighted diffs
│   └── file-index/          # Fuzzy file search
└── vim/                     # Vim mode implementation

What's Stubbed Out

Some internal Anthropic features weren't included in the leak or are behind private packages. These are stubbed with no-ops:

• Computer Use (@ant/computer-use-*) — screen control tools
• Chrome Integration (@ant/claude-for-chrome-mcp) — browser automation
• Sandbox Runtime (@anthropic-ai/sandbox-runtime) — sandboxed execution
• TungstenTool, REPLTool — internal-only tools
• Context Collapse — internal compaction feature

The core CLI, all standard tools (Bash, Edit, Read, Write, Grep, Glob, etc.), MCP support, and the full terminal UI work.

Build Details

The build script (build.ts) uses Bun's bundler to:

1. Bundle 4,500+ modules into a single dist/cli.js (~21 MB)
2. Define MACRO.* build-time constants (version, feedback channel)
3. Externalize optional native deps (sharp, react-devtools-core)

Feature flags from bun:bundle's feature() all return false — internal Anthropic features (voice mode, coordinator mode, etc.) are disabled.

License

This is leaked proprietary source code from Anthropic. Use at your own discretion.