(Alleged) Leaked source of Claude Code
1# Claude Code — Leaked Source (2026-03-31)
2
3> **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.
4
5---
6
7## How It Leaked
8
9[Chaofan Shou (@Fried_rice)](https://x.com/Fried_rice) discovered the leak and posted it publicly:
10
11> **"Claude code source code has been leaked via a map file in their npm registry!"**
12>
13> — [@Fried_rice, March 31, 2026](https://x.com/Fried_rice/status/2038894956459290963)
14
15The 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.
16
17---
18
19## Overview
20
21Claude 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.
22
23This repository contains the leaked `src/` directory.
24
25- **Leaked on**: 2026-03-31
26- **Language**: TypeScript
27- **Runtime**: Bun
28- **Terminal UI**: React + [Ink](https://github.com/vadimdemedes/ink) (React for CLI)
29- **Scale**: ~1,900 files, 512,000+ lines of code
30
31---
32
33## Directory Structure
34
35```
36src/
37├── main.tsx # Entrypoint (Commander.js-based CLI parser)
38├── commands.ts # Command registry
39├── tools.ts # Tool registry
40├── Tool.ts # Tool type definitions
41├── QueryEngine.ts # LLM query engine (core Anthropic API caller)
42├── context.ts # System/user context collection
43├── cost-tracker.ts # Token cost tracking
44│
45├── commands/ # Slash command implementations (~50)
46├── tools/ # Agent tool implementations (~40)
47├── components/ # Ink UI components (~140)
48├── hooks/ # React hooks
49├── services/ # External service integrations
50├── screens/ # Full-screen UIs (Doctor, REPL, Resume)
51├── types/ # TypeScript type definitions
52├── utils/ # Utility functions
53│
54├── bridge/ # IDE integration bridge (VS Code, JetBrains)
55├── coordinator/ # Multi-agent coordinator
56├── plugins/ # Plugin system
57├── skills/ # Skill system
58├── keybindings/ # Keybinding configuration
59├── vim/ # Vim mode
60├── voice/ # Voice input
61├── remote/ # Remote sessions
62├── server/ # Server mode
63├── memdir/ # Memory directory (persistent memory)
64├── tasks/ # Task management
65├── state/ # State management
66├── migrations/ # Config migrations
67├── schemas/ # Config schemas (Zod)
68├── entrypoints/ # Initialization logic
69├── ink/ # Ink renderer wrapper
70├── buddy/ # Companion sprite (Easter egg)
71├── native-ts/ # Native TypeScript utils
72├── outputStyles/ # Output styling
73├── query/ # Query pipeline
74└── upstreamproxy/ # Proxy configuration
75```
76
77---
78
79## Core Architecture
80
81### 1. Tool System (`src/tools/`)
82
83Every tool Claude Code can invoke is implemented as a self-contained module. Each tool defines its input schema, permission model, and execution logic.
84
85| Tool | Description |
86|---|---|
87| `BashTool` | Shell command execution |
88| `FileReadTool` | File reading (images, PDFs, notebooks) |
89| `FileWriteTool` | File creation / overwrite |
90| `FileEditTool` | Partial file modification (string replacement) |
91| `GlobTool` | File pattern matching search |
92| `GrepTool` | ripgrep-based content search |
93| `WebFetchTool` | Fetch URL content |
94| `WebSearchTool` | Web search |
95| `AgentTool` | Sub-agent spawning |
96| `SkillTool` | Skill execution |
97| `MCPTool` | MCP server tool invocation |
98| `LSPTool` | Language Server Protocol integration |
99| `NotebookEditTool` | Jupyter notebook editing |
100| `TaskCreateTool` / `TaskUpdateTool` | Task creation and management |
101| `SendMessageTool` | Inter-agent messaging |
102| `TeamCreateTool` / `TeamDeleteTool` | Team agent management |
103| `EnterPlanModeTool` / `ExitPlanModeTool` | Plan mode toggle |
104| `EnterWorktreeTool` / `ExitWorktreeTool` | Git worktree isolation |
105| `ToolSearchTool` | Deferred tool discovery |
106| `CronCreateTool` | Scheduled trigger creation |
107| `RemoteTriggerTool` | Remote trigger |
108| `SleepTool` | Proactive mode wait |
109| `SyntheticOutputTool` | Structured output generation |
110
111### 2. Command System (`src/commands/`)
112
113User-facing slash commands invoked with `/` prefix.
114
115| Command | Description |
116|---|---|
117| `/commit` | Create a git commit |
118| `/review` | Code review |
119| `/compact` | Context compression |
120| `/mcp` | MCP server management |
121| `/config` | Settings management |
122| `/doctor` | Environment diagnostics |
123| `/login` / `/logout` | Authentication |
124| `/memory` | Persistent memory management |
125| `/skills` | Skill management |
126| `/tasks` | Task management |
127| `/vim` | Vim mode toggle |
128| `/diff` | View changes |
129| `/cost` | Check usage cost |
130| `/theme` | Change theme |
131| `/context` | Context visualization |
132| `/pr_comments` | View PR comments |
133| `/resume` | Restore previous session |
134| `/share` | Share session |
135| `/desktop` | Desktop app handoff |
136| `/mobile` | Mobile app handoff |
137
138### 3. Service Layer (`src/services/`)
139
140| Service | Description |
141|---|---|
142| `api/` | Anthropic API client, file API, bootstrap |
143| `mcp/` | Model Context Protocol server connection and management |
144| `oauth/` | OAuth 2.0 authentication flow |
145| `lsp/` | Language Server Protocol manager |
146| `analytics/` | GrowthBook-based feature flags and analytics |
147| `plugins/` | Plugin loader |
148| `compact/` | Conversation context compression |
149| `policyLimits/` | Organization policy limits |
150| `remoteManagedSettings/` | Remote managed settings |
151| `extractMemories/` | Automatic memory extraction |
152| `tokenEstimation.ts` | Token count estimation |
153| `teamMemorySync/` | Team memory synchronization |
154
155### 4. Bridge System (`src/bridge/`)
156
157A bidirectional communication layer connecting IDE extensions (VS Code, JetBrains) with the Claude Code CLI.
158
159- `bridgeMain.ts` — Bridge main loop
160- `bridgeMessaging.ts` — Message protocol
161- `bridgePermissionCallbacks.ts` — Permission callbacks
162- `replBridge.ts` — REPL session bridge
163- `jwtUtils.ts` — JWT-based authentication
164- `sessionRunner.ts` — Session execution management
165
166### 5. Permission System (`src/hooks/toolPermission/`)
167
168Checks 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.).
169
170### 6. Feature Flags
171
172Dead code elimination via Bun's `bun:bundle` feature flags:
173
174```typescript
175import { feature } from 'bun:bundle'
176
177// Inactive code is completely stripped at build time
178const voiceCommand = feature('VOICE_MODE')
179 ? require('./commands/voice/index.js').default
180 : null
181```
182
183Notable flags: `PROACTIVE`, `KAIROS`, `BRIDGE_MODE`, `DAEMON`, `VOICE_MODE`, `AGENT_TRIGGERS`, `MONITOR_TOOL`
184
185---
186
187## Key Files in Detail
188
189### `QueryEngine.ts` (~46K lines)
190
191The core engine for LLM API calls. Handles streaming responses, tool-call loops, thinking mode, retry logic, and token counting.
192
193### `Tool.ts` (~29K lines)
194
195Defines base types and interfaces for all tools — input schemas, permission models, and progress state types.
196
197### `commands.ts` (~25K lines)
198
199Manages registration and execution of all slash commands. Uses conditional imports to load different command sets per environment.
200
201### `main.tsx`
202
203Commander.js-based CLI parser + React/Ink renderer initialization. At startup, parallelizes MDM settings, keychain prefetch, and GrowthBook initialization for faster boot.
204
205---
206
207## Tech Stack
208
209| Category | Technology |
210|---|---|
211| Runtime | [Bun](https://bun.sh) |
212| Language | TypeScript (strict) |
213| Terminal UI | [React](https://react.dev) + [Ink](https://github.com/vadimdemedes/ink) |
214| CLI Parsing | [Commander.js](https://github.com/tj/commander.js) (extra-typings) |
215| Schema Validation | [Zod v4](https://zod.dev) |
216| Code Search | [ripgrep](https://github.com/BurntSushi/ripgrep) (via GrepTool) |
217| Protocols | [MCP SDK](https://modelcontextprotocol.io), LSP |
218| API | [Anthropic SDK](https://docs.anthropic.com) |
219| Telemetry | OpenTelemetry + gRPC |
220| Feature Flags | GrowthBook |
221| Auth | OAuth 2.0, JWT, macOS Keychain |
222
223---
224
225## Notable Design Patterns
226
227### Parallel Prefetch
228
229Startup time is optimized by prefetching MDM settings, keychain reads, and API preconnect in parallel — before heavy module evaluation begins.
230
231```typescript
232// main.tsx — fired as side-effects before other imports
233startMdmRawRead()
234startKeychainPrefetch()
235```
236
237### Lazy Loading
238
239Heavy modules (OpenTelemetry ~400KB, gRPC ~700KB) are deferred via dynamic `import()` until actually needed.
240
241### Agent Swarms
242
243Sub-agents are spawned via `AgentTool`, with `coordinator/` handling multi-agent orchestration. `TeamCreateTool` enables team-level parallel work.
244
245### Skill System
246
247Reusable workflows defined in `skills/` and executed through `SkillTool`. Users can add custom skills.
248
249### Plugin Architecture
250
251Built-in and third-party plugins are loaded through the `plugins/` subsystem.
252
253---
254
255## Disclaimer
256
257This 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](https://www.anthropic.com).