Claude Code — Leaked Source

The full source code of Anthropic's Claude Code CLI, leaked on March 31, 2026

The original unmodified leaked source is preserved in the backup branch.

---

Spend less time reading code, more time building.

---

Table of Contents

• How It Leaked
• What Is Claude Code?
• Documentation
• Explore with MCP Server
• Directory Structure
• Architecture
  • Tool System
  • Command System
  • Service Layer
  • Bridge System
  • Permission System
  • Feature Flags
• Key Files
• Tech Stack
• Design Patterns
• GitPretty Setup
• Contributing
• Disclaimer

---

How It Leaked

Chaofan Shou (@Fried_rice) discovered that the published npm package for Claude Code included a .map file referencing the full, unobfuscated TypeScript source — downloadable as a zip from Anthropic's R2 storage bucket.

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

— @Fried_rice, March 31, 2026

---

What Is Claude Code?

Claude Code is Anthropic's official CLI tool for interacting with Claude directly from the terminal — editing files, running commands, searching codebases, managing git workflows, and more. This repository contains the leaked src/ directory.

| | | |---|---| | Leaked | 2026-03-31 | | Language | TypeScript (strict) | | Runtime | Bun | | Terminal UI | React + Ink | | Scale | ~1,900 files · 512,000+ lines of code |

---

� Documentation

For in-depth guides, see the docs/ directory:

| Guide | Description | |-------|-------------| | Architecture | Core pipeline, startup sequence, state management, rendering, data flow | | Tools Reference | Complete catalog of all ~40 agent tools with categories and permission model | | Commands Reference | All ~85 slash commands organized by category | | Subsystems Guide | Deep dives into Bridge, MCP, Permissions, Plugins, Skills, Tasks, Memory, Voice | | Exploration Guide | How to navigate the codebase — study paths, grep patterns, key files |

Also see: CONTRIBUTING.md · MCP Server README

---

�🔍 Explore with MCP Server

This repo ships an MCP server that lets any MCP-compatible client (Claude Code, Claude Desktop, VS Code Copilot, Cursor) explore the full source interactively.

Install from npm

The MCP server is published as warrioraashuu-codemaster on npm — no need to clone the repo:

# Claude Code
claude mcp add warrioraashuu-codemaster -- npx -y warrioraashuu-codemaster

One-liner setup (from source)

git clone https://github.com/codeaashu/claude-code.git ~/claude-code \
  && cd ~/claude-code/mcp-server \
  && npm install && npm run build \
  && claude mcp add claude-code-explorer -- node ~/claude-code/mcp-server/dist/index.js

# 1. Clone the repo
git clone https://github.com/codeaashu/claude-code.git
cd claude-code/mcp-server

# 2. Install & build
npm install && npm run build

# 3. Register with Claude Code
claude mcp add claude-code-explorer -- node /absolute/path/to/claude-code/mcp-server/dist/index.js

Replace /absolute/path/to/claude-code with your actual clone path.

VS Code — add to .vscode/mcp.json:

{
  "servers": {
    "claude-code-explorer": {
      "type": "stdio",
      "command": "node",
      "args": ["${workspaceFolder}/mcp-server/dist/index.js"],
      "env": { "CLAUDE_CODE_SRC_ROOT": "${workspaceFolder}/src" }
    }
  }
}

Claude Desktop — add to your config file:

{
  "mcpServers": {
    "claude-code-explorer": {
      "command": "node",
      "args": ["/absolute/path/to/claude-code/mcp-server/dist/index.js"],
      "env": { "CLAUDE_CODE_SRC_ROOT": "/absolute/path/to/claude-code/src" }
    }
  }
}

Cursor — add to ~/.cursor/mcp.json (same format as Claude Desktop).

Available tools & prompts

| Tool | Description | |------|-------------| | list_tools | List all ~40 agent tools with source files | | list_commands | List all ~50 slash commands with source files | | get_tool_source | Read full source of any tool (e.g. BashTool, FileEditTool) | | get_command_source | Read source of any slash command (e.g. review, mcp) | | read_source_file | Read any file from src/ by path | | search_source | Grep across the entire source tree | | list_directory | Browse src/ directories | | get_architecture | High-level architecture overview |

| Prompt | Description | |--------|-------------| | explain_tool | Deep-dive into how a specific tool works | | explain_command | Understand a slash command's implementation | | architecture_overview | Guided tour of the full architecture | | how_does_it_work | Explain any subsystem (permissions, MCP, bridge, etc.) | | compare_tools | Side-by-side comparison of two tools |

Try asking: "How does the BashTool work?" · "Search for where permissions are checked" · "Show me the /review command source"

Custom source path / Remove

# Custom source location
claude mcp add claude-code-explorer -e CLAUDE_CODE_SRC_ROOT=/path/to/src -- node /path/to/mcp-server/dist/index.js

# Remove
claude mcp remove claude-code-explorer

---

Directory Structure

src/
├── main.tsx                 # Entrypoint — Commander.js CLI parser + React/Ink renderer
├── QueryEngine.ts           # Core LLM API caller (~46K lines)
├── Tool.ts                  # Tool type definitions (~29K lines)
├── commands.ts              # Command registry (~25K lines)
├── tools.ts                 # Tool registry
├── context.ts               # System/user context collection
├── cost-tracker.ts          # Token cost tracking
│
├── tools/                   # Agent tool implementations (~40)
├── commands/                # Slash command implementations (~50)
├── components/              # Ink UI components (~140)
├── services/                # External service integrations
├── hooks/                   # React hooks (incl. permission checks)
├── types/                   # TypeScript type definitions
├── utils/                   # Utility functions
├── screens/                 # Full-screen UIs (Doctor, REPL, Resume)
│
├── bridge/                  # IDE integration (VS Code, JetBrains)
├── coordinator/             # Multi-agent orchestration
├── plugins/                 # Plugin system
├── skills/                  # Skill system
├── server/                  # Server mode
├── remote/                  # Remote sessions
├── memdir/                  # Persistent memory directory
├── tasks/                   # Task management
├── state/                   # State management
│
├── voice/                   # Voice input
├── vim/                     # Vim mode
├── keybindings/             # Keybinding configuration
├── schemas/                 # Config schemas (Zod)
├── migrations/              # Config migrations
├── entrypoints/             # Initialization logic
├── query/                   # Query pipeline
├── ink/                     # Ink renderer wrapper
├── buddy/                   # Companion sprite (Easter egg 🐣)
├── native-ts/               # Native TypeScript utils
├── outputStyles/            # Output styling
└── upstreamproxy/           # Proxy configuration

---

Architecture

1. Tool System

src/tools/ — Every tool Claude can invoke is a self-contained module with its own input schema, permission model, and execution logic.

| Tool | Description | |---|---| | File I/O | | | FileReadTool | Read files (images, PDFs, notebooks) | | FileWriteTool | Create / overwrite files | | FileEditTool | Partial modification (string replacement) | | NotebookEditTool | Jupyter notebook editing | | Search | | | GlobTool | File pattern matching | | GrepTool | ripgrep-based content search | | WebSearchTool | Web search | | WebFetchTool | Fetch URL content | | Execution | | | BashTool | Shell command execution | | SkillTool | Skill execution | | MCPTool | MCP server tool invocation | | LSPTool | Language Server Protocol integration | | Agents & Teams | | | AgentTool | Sub-agent spawning | | SendMessageTool | Inter-agent messaging | | TeamCreateTool / TeamDeleteTool | Team management | | TaskCreateTool / TaskUpdateTool | Task management | | Mode & State | | | EnterPlanModeTool / ExitPlanModeTool | Plan mode toggle | | EnterWorktreeTool / ExitWorktreeTool | Git worktree isolation | | ToolSearchTool | Deferred tool discovery | | SleepTool | Proactive mode wait | | CronCreateTool | Scheduled triggers | | RemoteTriggerTool | Remote trigger | | SyntheticOutputTool | Structured output generation |

2. Command System

src/commands/ — User-facing slash commands invoked with / in the REPL.

| Command | Description | | Command | Description | |---|---|---|---|---| | /commit | Git commit | | /memory | Persistent memory | | /review | Code review | | /skills | Skill management | | /compact | Context compression | | /tasks | Task management | | /mcp | MCP server management | | /vim | Vim mode toggle | | /config | Settings | | /diff | View changes | | /doctor | Environment diagnostics | | /cost | Check usage cost | | /login / /logout | Auth | | /theme | Change theme | | /context | Context visualization | | /share | Share session | | /pr_comments | PR comments | | /resume | Restore session | | /desktop | Desktop handoff | | /mobile | Mobile handoff |

3. Service Layer

src/services/ — External integrations and core infrastructure.

| Service | Description | |---|---| | api/ | Anthropic API client, file API, bootstrap | | mcp/ | Model Context Protocol connection & management | | oauth/ | OAuth 2.0 authentication | | lsp/ | Language Server Protocol manager | | analytics/ | GrowthBook feature flags & analytics | | plugins/ | Plugin loader | | compact/ | Conversation context compression | | extractMemories/ | Automatic memory extraction | | teamMemorySync/ | Team memory synchronization | | tokenEstimation.ts | Token count estimation | | policyLimits/ | Organization policy limits | | remoteManagedSettings/ | Remote managed settings |

4. Bridge System

src/bridge/ — Bidirectional communication layer connecting IDE extensions (VS Code, JetBrains) with the CLI.

Key files: bridgeMain.ts (main loop) · bridgeMessaging.ts (protocol) · bridgePermissionCallbacks.ts (permission callbacks) · replBridge.ts (REPL session) · jwtUtils.ts (JWT auth) · sessionRunner.ts (session execution)

5. Permission System

src/hooks/toolPermission/ — Checks permissions on every tool invocation.

Prompts the user for approval/denial or auto-resolves based on the configured permission mode: default, plan, bypassPermissions, auto, etc.

6. Feature Flags

Dead code elimination at build time via Bun's bun:bundle:

import { feature } from 'bun:bundle'

const voiceCommand = feature('VOICE_MODE')
  ? require('./commands/voice/index.js').default
  : null

Notable flags: PROACTIVE · KAIROS · BRIDGE_MODE · DAEMON · VOICE_MODE · AGENT_TRIGGERS · MONITOR_TOOL

---

Key Files

| File | Lines | Purpose | |------|------:|---------| | QueryEngine.ts | ~46K | Core LLM API engine — streaming, tool loops, thinking mode, retries, token counting | | Tool.ts | ~29K | Base types/interfaces for all tools — input schemas, permissions, progress state | | commands.ts | ~25K | Command registration & execution with conditional per-environment imports | | main.tsx | — | CLI parser + React/Ink renderer; parallelizes MDM, keychain, and GrowthBook on startup |

---

Tech Stack

| Category | Technology | |---|---| | Runtime | Bun | | Language | TypeScript (strict) | | Terminal UI | React + Ink | | CLI Parsing | Commander.js (extra-typings) | | Schema Validation | Zod v4 | | Code Search | ripgrep (via GrepTool) | | Protocols | MCP SDK · LSP | | API | Anthropic SDK | | Telemetry | OpenTelemetry + gRPC | | Feature Flags | GrowthBook | | Auth | OAuth 2.0 · JWT · macOS Keychain |

---

Design Patterns

MDM settings, keychain reads, and API preconnect fire in parallel as side-effects before heavy module evaluation:

// main.tsx
startMdmRawRead()
startKeychainPrefetch()

OpenTelemetry (~400KB) and gRPC (~700KB) are loaded via dynamic import() only when needed.

Sub-agents spawn via AgentTool, with coordinator/ handling orchestration. TeamCreateTool enables team-level parallel work.

Defined in skills/ and executed through SkillTool. Users can add custom skills.

Built-in and third-party plugins loaded through the plugins/ subsystem.

---

GitPretty Setup

# Apply emoji commits
bash ./gitpretty-apply.sh .

# Optional: install hooks for future commits
bash ./gitpretty-apply.sh . --hooks

# Push as usual
git push origin main

---

Contributing

Contributions to documentation, the MCP server, and exploration tooling are welcome. See CONTRIBUTING.md for guidelines.

Note: The src/ directory is the original leaked source and should not be modified.

---

Disclaimer

This repository archives source code leaked from Anthropic's npm registry on 2026-03-31. All original source code is the property of Anthropic. This is not an official release and is not licensed for redistribution. Contact aashuu ✦ for any comments.

---