On March 31, 2026, the full source code of Anthropic's Claude Code CLI was leaked via a
.mapfile exposed in their npm registry.
Chaofan Shou (@Fried_rice) discovered the leak and posted it publicly:
"Claude code source code has been leaked via a map file in their npm registry!"
The source map file in the published npm package contained a reference to the full, unobfuscated TypeScript source, which was downloadable as a zip archive from Anthropic's R2 storage bucket.
Claude Code is Anthropic's official CLI tool that lets you interact with Claude directly from the terminal to perform software engineering tasks — editing files, running commands, searching codebases, managing git workflows, and more.
This repository contains the leaked src/ directory.
- Leaked on: 2026-03-31
- Language: TypeScript
- Runtime: Bun
- Terminal UI: React + Ink (React for CLI)
- Scale: ~1,900 files, 512,000+ lines of code
src/
├── main.tsx # Entrypoint (Commander.js-based CLI parser)
├── commands.ts # Command registry
├── tools.ts # Tool registry
├── Tool.ts # Tool type definitions
├── QueryEngine.ts # LLM query engine (core Anthropic API caller)
├── context.ts # System/user context collection
├── cost-tracker.ts # Token cost tracking
│
├── commands/ # Slash command implementations (~50)
├── tools/ # Agent tool implementations (~40)
├── components/ # Ink UI components (~140)
├── hooks/ # React hooks
├── services/ # External service integrations
├── screens/ # Full-screen UIs (Doctor, REPL, Resume)
├── types/ # TypeScript type definitions
├── utils/ # Utility functions
│
├── bridge/ # IDE integration bridge (VS Code, JetBrains)
├── coordinator/ # Multi-agent coordinator
├── plugins/ # Plugin system
├── skills/ # Skill system
├── keybindings/ # Keybinding configuration
├── vim/ # Vim mode
├── voice/ # Voice input
├── remote/ # Remote sessions
├── server/ # Server mode
├── memdir/ # Memory directory (persistent memory)
├── tasks/ # Task management
├── state/ # State management
├── migrations/ # Config migrations
├── schemas/ # Config schemas (Zod)
├── entrypoints/ # Initialization logic
├── ink/ # Ink renderer wrapper
├── buddy/ # Companion sprite (Easter egg)
├── native-ts/ # Native TypeScript utils
├── outputStyles/ # Output styling
├── query/ # Query pipeline
└── upstreamproxy/ # Proxy configuration
Every tool Claude Code can invoke is implemented as a self-contained module. Each tool defines its input schema, permission model, and execution logic.
| Tool | Description |
|---|---|
BashTool | Shell command execution |
FileReadTool | File reading (images, PDFs, notebooks) |
FileWriteTool | File creation / overwrite |
FileEditTool | Partial file modification (string replacement) |
GlobTool | File pattern matching search |
GrepTool | ripgrep-based content search |
WebFetchTool | Fetch URL content |
WebSearchTool | Web search |
AgentTool | Sub-agent spawning |
SkillTool | Skill execution |
MCPTool | MCP server tool invocation |
LSPTool | Language Server Protocol integration |
NotebookEditTool | Jupyter notebook editing |
TaskCreateTool / TaskUpdateTool | Task creation and management |
SendMessageTool | Inter-agent messaging |
TeamCreateTool / TeamDeleteTool | Team agent management |
EnterPlanModeTool / ExitPlanModeTool | Plan mode toggle |
EnterWorktreeTool / ExitWorktreeTool | Git worktree isolation |
ToolSearchTool | Deferred tool discovery |
CronCreateTool | Scheduled trigger creation |
RemoteTriggerTool | Remote trigger |
SleepTool | Proactive mode wait |
SyntheticOutputTool | Structured output generation |
User-facing slash commands invoked with / prefix.
| Command | Description |
|---|---|
/commit | Create a git commit |
/review | Code review |
/compact | Context compression |
/mcp | MCP server management |
/config | Settings management |
/doctor | Environment diagnostics |
/login / /logout | Authentication |
/memory | Persistent memory management |
/skills | Skill management |
/tasks | Task management |
/vim | Vim mode toggle |
/diff | View changes |
/cost | Check usage cost |
/theme | Change theme |
/context | Context visualization |
/pr_comments | View PR comments |
/resume | Restore previous session |
/share | Share session |
/desktop | Desktop app handoff |
/mobile | Mobile app handoff |
| Service | Description |
|---|---|
api/ | Anthropic API client, file API, bootstrap |
mcp/ | Model Context Protocol server connection and management |
oauth/ | OAuth 2.0 authentication flow |
lsp/ | Language Server Protocol manager |
analytics/ | GrowthBook-based feature flags and analytics |
plugins/ | Plugin loader |
compact/ | Conversation context compression |
policyLimits/ | Organization policy limits |
remoteManagedSettings/ | Remote managed settings |
extractMemories/ | Automatic memory extraction |
tokenEstimation.ts | Token count estimation |
teamMemorySync/ | Team memory synchronization |
A bidirectional communication layer connecting IDE extensions (VS Code, JetBrains) with the Claude Code CLI.
bridgeMain.ts— Bridge main loopbridgeMessaging.ts— Message protocolbridgePermissionCallbacks.ts— Permission callbacksreplBridge.ts— REPL session bridgejwtUtils.ts— JWT-based authenticationsessionRunner.ts— Session execution management
Checks permissions on every tool invocation. Either prompts the user for approval/denial or automatically resolves based on the configured permission mode (default, plan, bypassPermissions, auto, etc.).
Dead code elimination via Bun's bun:bundle feature flags:
import{feature}from'bun:bundle'// Inactive code is completely stripped at build timeconstvoiceCommand=feature('VOICE_MODE')
? require('./commands/voice/index.js').default
: nullNotable flags: PROACTIVE, KAIROS, BRIDGE_MODE, DAEMON, VOICE_MODE, AGENT_TRIGGERS, MONITOR_TOOL
The core engine for LLM API calls. Handles streaming responses, tool-call loops, thinking mode, retry logic, and token counting.
Defines base types and interfaces for all tools — input schemas, permission models, and progress state types.
Manages registration and execution of all slash commands. Uses conditional imports to load different command sets per environment.
Commander.js-based CLI parser + React/Ink renderer initialization. At startup, parallelizes MDM settings, keychain prefetch, and GrowthBook initialization for faster boot.
| 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 |
Startup time is optimized by prefetching MDM settings, keychain reads, and API preconnect in parallel — before heavy module evaluation begins.
// main.tsx — fired as side-effects before other importsstartMdmRawRead()startKeychainPrefetch()Heavy modules (OpenTelemetry ~400KB, gRPC ~700KB) are deferred via dynamic import() until actually needed.
Sub-agents are spawned via AgentTool, with coordinator/ handling multi-agent orchestration. TeamCreateTool enables team-level parallel work.
Reusable workflows defined in skills/ and executed through SkillTool. Users can add custom skills.
Built-in and third-party plugins are loaded through the plugins/ subsystem.
This repository archives source code that was leaked from Anthropic's npm registry on 2026-03-31. All original source code is the property of Anthropic.