📑 Table of Contents

• Overview
• ⭐ Star History
• 🏗️ Project Structure
• 🧠 Key Architectural Insights
• 🔨 Building from Source
• ❓ Known Missing Files
• ⚖️ Disclaimer
• 📌 Source Version

Overview

This repository contains the reverse-engineered TypeScript source code from Anthropic's Claude Code CLI tool.

The official npm package ships as a single minified cli.js bundle (~12MB); this repo restores the original module structure with readable names, comments, and type annotations — making it possible to study how a state-of-the-art AI coding agent is wired internally.

🎓 Built for learning, security research, and architectural curiosity — not for redistribution or bypassing the official package.

⭐ Star History

🏗️ Project Structure

├── package.json          # Dependencies & build scripts
├── tsconfig.json         # TypeScript configuration
├── src/                  # Source code (deobfuscated)
│   ├── entrypoints/      # CLI, SDK, MCP entry points
│   ├── tools/            # 40+ tool implementations
│   ├── AgentTool/        # Sub-agent spawning & orchestration
│   ├── BashTool/         # Shell command execution with sandbox
│   ├── FileEditTool/     # String replacement file editing
│   ├── FileReadTool/     # File reading (text, PDF, images)
│   ├── FileWriteTool/    # File creation/overwrite
│   ├── GlobTool/         # File pattern matching
│   ├── GrepTool/         # Content search (ripgrep-based)
│   ├── WebFetchTool/     # URL fetching & content extraction
│   ├── WebSearchTool/    # Web search integration
│   ├── SkillTool/        # Slash command / skill execution
│   ├── LSPTool/          # Language Server Protocol integration
│   ├── NotebookEditTool/ # Jupyter notebook editing
│   └── ...               # TaskCreate/Get/Update/List/Stop, Cron, MCP, etc.
├── bridge/               # IDE integration & remote control (CCR)
├── query/                # Core query engine & token budget
├── query.ts              # Main conversation loop (~68K lines)
├── QueryEngine.ts        # High-level session management
├── commands/             # 88+ slash commands
├── commands.ts           # Command registry with feature gates
├── components/           # React + Ink TUI components
├── services/             # API, analytics, MCP, telemetry
├── state/                # Zustand-like app state management
├── context/              # System prompt & context assembly
├── hooks/                # Pre/post tool execution hooks
├── skills/               # Built-in skill definitions
├── plugins/              # Plugin system (manifest, marketplace)
├── coordinator/          # Multi-agent coordination mode
├── buddy/                # Virtual companion system (Easter egg)
├── vim/                  # Full Vim keybinding support
├── voice/                # Voice input mode
├── ink/                  # Custom Ink renderer & reconciler
├── native-ts/            # TS ports of native modules (yoga, nucleo, syntect)
├── remote/               # Remote session management
├── server/               # Direct connect server
├── memdir/               # Auto-memory system (MEMORY.md)
├── keybindings/          # Keyboard shortcut system
├── migrations/           # Version upgrade migrations
├── upstreamproxy/        # Container HTTPS proxy (CCR)
├── schemas/              # Zod validation schemas
├── types/                # TypeScript type definitions
├── utils/                # Utilities (permissions, sandbox, config, etc.)
├── constants/            # Prompts, keys, system constants
├── tasks/                # Background task types (Agent, Shell, Workflow)
│   ├── Tool.ts           # Base tool interface & registry
│   ├── tools.ts          # Tool list with feature-gated imports
│   ├── cost-tracker.ts   # API cost tracking
│   ├── history.ts        # Conversation history (JSONL)
│   └── setup.ts          # Initialization & configuration
└── dist/                 # Build output (not committed)

🧠 Key Architectural Insights

Build System

• Built with Bun bundler — uses bun:bundle feature() for compile-time dead code elimination (DCE)
• MACRO.* build-time constants (VERSION, BUILD_TIME, etc.) injected via --define
• React Compiler (react/compiler-runtime) for optimized component rendering
• Single-file output: all 5,066 modules bundled into one cli.js

Feature Gates

Internal feature flags control functionality via feature() from bun:bundle:

• PROACTIVE / KAIROS — Proactive agent capabilities
• AGENT_TRIGGERS / AGENT_TRIGGERS_REMOTE — Scheduled/remote agent execution
• MONITOR_TOOL — Live monitoring tool
• ABLATION_BASELINE — A/B testing baseline
• KAIROS_GITHUB_WEBHOOKS — GitHub webhook subscriptions

Internal-Only Features

Some tools/packages are restricted to Anthropic employees (USER_TYPE === 'ant'):

• REPLTool — Interactive REPL execution
• SuggestBackgroundPRTool — Background PR suggestions
• @ant/claude-for-chrome-mcp — Chrome browser integration
• @anthropic-ai/sandbox-runtime — Sandbox isolation runtime

Tool System

• All tools implement a common interface (Tool from Tool.ts)
• Input validation via Zod with lazySchema() for deferred initialization
• Permission system: canUseTool() hooks with caching
• Concurrent file edit protection via timestamp + content change detection
• ToolSearchTool enables lazy tool discovery (deferred tool loading)

State Management

• AppStateStore — Zustand-like reactive state for the TUI
• QueryEngine — Manages conversation sessions, message history, compaction
• Session persistence — JSONL-based history with paste storage

🔨 Building from Source

Prerequisites

• Bun >= 1.0
• Node.js >= 18

Steps

# Install dependencies
bun install

# Build (you'll need to create stubs for internal @ant/* packages)
bun build src/entrypoints/cli.tsx --outdir dist --target node \
  --external "react/compiler-runtime" \
  --define "MACRO.VERSION='\"2.1.76\"'" \
  --define "MACRO.BUILD_TIME='\"$(date -I)\"'" \
  --define "MACRO.FEEDBACK_CHANNEL='\"stable\"'" \
  --define "MACRO.ISSUES_EXPLAINER='\"report issues\"'" \
  --define "MACRO.PACKAGE_URL='\"\"'" \
  --define "MACRO.NATIVE_PACKAGE_URL='\"\"'" \
  --define "MACRO.VERSION_CHANGELOG='\"\"'"

# Patch react/compiler-runtime import
sed -i 's|from "react/compiler-runtime"|from "./react-compiler-runtime.js"|g' dist/cli.js

# Run
node dist/cli.js --version

Note: ~10 source files are missing from this deobfuscation (internal tools, some type definitions). Stubs are needed for: @ant/* packages, @anthropic-ai/sandbox-runtime, REPLTool, TungstenTool, color-diff-napi, modifiers-napi.

❓ Known Missing Files

⚖️ Disclaimer

⚠️ Educational use only.

This repository is published strictly for educational and research purposes — reverse-engineering study, security research, and architectural learning.

• All intellectual property rights belong to Anthropic PBC.
• The original package is governed by Anthropic's legal agreements.
• Do not use this repository to bypass licensing, redistribute, or misrepresent the source.
• If you represent Anthropic and have concerns, please open an issue — issues will be addressed promptly.

📌 Source Version

• Package: @anthropic-ai/claude-code
• Version: 2.1.76
• Date: 2026-03-26