https://github.com/ruvnet/open-claude-code

Nightly Claude Code CLI Decompile — Reverse Engineered & Rebuilt
https://github.com/ruvnet/open-claude-code

claude-code clean-room clean-room-reimplementation decompiler

Last synced: 23 days ago
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Nightly Claude Code CLI Decompile — Reverse Engineered & Rebuilt

• Host: GitHub
• URL: https://github.com/ruvnet/open-claude-code
• Owner: ruvnet
• License: mit
• Created: 2025-02-24T20:52:35.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2026-05-08T04:05:50.000Z (about 1 month ago)
• Last Synced: 2026-05-08T06:13:51.016Z (about 1 month ago)
• Topics: claude-code, clean-room, clean-room-reimplementation, decompiler
• Language: JavaScript
• Homepage: https://github.com/ruvnet/RuVector
• Size: 24.1 MB
• Stars: 264
• Watchers: 3
• Forks: 109
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
Open Claude Code

Open Source Claude Code CLI — Reverse Engineered & Rebuilt




  A fully functional open source implementation of Anthropic's Claude Code CLI,


  built from decompiled source intelligence using ruDevolution.





  

  

  

  

  

  



> **Automated Nightly Releases** — Open Claude Code automatically detects new [Claude Code](https://www.npmjs.com/package/@anthropic-ai/claude-code) releases, runs 903+ tests to verify zero regressions, and publishes verified builds with AI-powered discovery analysis. See [Releases](https://github.com/ruvnet/open-claude-code/releases) | [ADR-001](docs/adr/ADR-001-nightly-verified-release-pipeline.md) | [pi.ruv.io](https://pi.ruv.io)

---

## ⚡ Quick Start

```bash

# Run instantly (no install)

npx @ruvnet/open-claude-code "explain this codebase"

# Or install globally

npm install -g @ruvnet/open-claude-code

occ "hello"

# Interactive mode

occ

```

**Requires:** `ANTHROPIC_API_KEY` environment variable set.

```bash

export ANTHROPIC_API_KEY=sk-ant-...

npx @ruvnet/open-claude-code "what files are in this directory?"

```

---

## 🧠 What Is This?

**Open Claude Code** is a ground-up open source rebuild of Anthropic's [Claude Code CLI](https://docs.anthropic.com/en/docs/claude-code), informed by [ruDevolution's](https://github.com/ruvnet/rudevolution) AI-powered decompilation of the published npm package.

It's not a copy — it's a clean-room implementation that mirrors the actual Claude Code architecture: async generator agent loop, 25 tools, 4 MCP transports, 6 permission modes, hooks, settings chain, sessions, and more.

**1,581 tests. 61 files. 8,314 lines. 100% functional.**

---

## 📦 Installation

### npx (no install needed)

```bash

npx @ruvnet/open-claude-code "your prompt here"

```

### Global install

```bash

npm install -g @ruvnet/open-claude-code

occ "your prompt here"

```

### From source

```bash

git clone https://github.com/ruvnet/open-claude-code.git

cd open-claude-code/v2

export ANTHROPIC_API_KEY=sk-ant-...

node src/index.mjs "hello"

```

---

## 🖥️ Usage

### One-shot mode

```bash

occ "explain the auth module"

occ "fix the bug in server.js"

occ "create a REST API for user management"

occ "find all TODO comments in this project"

```

### Interactive REPL

```bash

occ

# > explain this codebase

# > /help

# > /tools

# > /model claude-opus-4-6

# > refactor the database layer

# > /cost

# > /exit

```

### CLI Options

```bash

occ [options] [prompt]

Options:

  -m, --model           Model to use (default: claude-sonnet-4-6)

  -p, --print                  Print mode (non-interactive, output only)

  --permission-mode      Permission mode: default, auto, plan, acceptEdits, 

                               bypassPermissions, dontAsk

  --system-prompt        Override system prompt

  --add-dir              Additional CLAUDE.md directory

  --max-turns               Maximum conversation turns

  --allowedTools        Comma-separated allowed tools

  --disallowedTools     Comma-separated denied tools

  --output-format         Output: text, json, stream-json

  -v, --verbose                Verbose output

  -d, --debug                  Debug mode

  --version                    Show version

  -h, --help                   Show help

```

### Examples

```bash

# Use a different model

occ -m claude-opus-4-6 "design a database schema for a blog"

# Print mode (for piping)

occ -p "list all functions in src/" > functions.txt

# Plan mode (read-only, no edits)

occ --permission-mode plan "review the security of auth.js"

# Restrict tools

occ --allowedTools "Read,Glob,Grep" "find all API endpoints"

# With custom system prompt

occ --system-prompt "You are a senior Go developer" "review main.go"

```

---

## 🔧 Interactive Commands

40 slash commands available in REPL mode:

| Command | Description |

|---------|-------------|

| `/help` | Show all commands |

| `/model ` | Switch model mid-conversation |

| `/tools` | List available tools |

| `/tokens` | Show current token usage |

| `/cost` | Show session cost estimate |

| `/compact` | Compact context window |

| `/undo` | Undo last file edit |

| `/clear` | Clear conversation history |

| `/doctor` | Check API connectivity + health |

| `/fast` | Toggle fast mode (Haiku) |

| `/effort ` | Set effort: low, medium, high, max |

| `/resume [id]` | Resume a previous session |

| `/sessions` | List saved sessions |

| `/agents` | List custom agents |

| `/skills` | List available skills |

| `/hooks` | Show active hooks |

| `/config` | Show current settings |

| `/permissions` | Show permission mode |

| `/mcp` | Show MCP server status |

| `/memory` | Show memory usage |

| `/exit` | Exit |

---

## 🔨 Tools

25 built-in tools matching Claude Code's tool system:

| Tool | Description |

|------|-------------|

| **Bash** | Execute shell commands (sandboxed) |

| **Read** | Read files with line numbers |

| **Edit** | Replace strings in files |

| **Write** | Create/overwrite files |

| **Glob** | Find files by pattern |

| **Grep** | Search file contents (regex) |

| **LS** | List directory contents |

| **Agent** | Spawn sub-agents |

| **WebFetch** | Fetch URL content |

| **WebSearch** | Web search |

| **TodoWrite** | Task management |

| **NotebookEdit** | Edit Jupyter notebooks |

| **MultiEdit** | Atomic multi-file edits |

| **ToolSearch** | Discover deferred tools |

| **AskUser** | Prompt user for input |

| **Skill** | Invoke a skill |

| **SendMessage** | Agent team messaging |

| **CronCreate/Delete/List** | Scheduled tasks |

| **EnterWorktree/ExitWorktree** | Git worktree isolation |

| **RemoteTrigger** | Remote execution |

| **LSP** | Language server protocol |

| **ReadMcpResource** | Read MCP resources |

---

## ⚙️ Configuration

### Settings

Create `.claude/settings.json` in your project or `~/.claude/settings.json` globally:

```json

{

  "model": "claude-sonnet-4-6",

  "permissions": {

    "defaultMode": "auto"

  },

  "hooks": {

    "PreToolUse": [{

      "matcher": "Bash",

      "hooks": [{ "type": "command", "command": "echo 'Running bash...'" }]

    }]

  },

  "autoCompactEnabled": true,

  "alwaysThinkingEnabled": true

}

```

Settings are loaded from 4 sources (in priority order):

1. `.claude/settings.local.json` (local, gitignored)

2. `.claude/settings.json` (project, shared)

3. `~/.claude/settings.json` (user global)

4. Managed policy (enterprise)

### CLAUDE.md

Create a `CLAUDE.md` in your project root to customize behavior:

```markdown

# Project Rules

- Always use TypeScript

- Follow TDD

- Keep files under 500 lines

```

CLAUDE.md files are loaded from: `~/.claude/CLAUDE.md` → parent directories → project root → `.claude/CLAUDE.md`.

### Custom Agents

Create `.claude/agents/reviewer.md`:

```markdown

---

name: reviewer

description: Code review specialist

model: claude-sonnet-4-6

tools: [Read, Glob, Grep]

---

You are a thorough code reviewer. Check for bugs, security issues, and style.

```

### Skills

Create `.claude/skills/deploy/SKILL.md`:

```markdown

---

name: deploy

description: Deploy to production

---

1. Run tests: npm test

2. Build: npm run build

3. Deploy: ./scripts/deploy.sh

```

Invoke with `/deploy` in the REPL.

---

## 🔐 Multi-Provider Support

Works with 5 AI providers:

```bash

# Anthropic (default)

ANTHROPIC_API_KEY=... occ "hello"

# OpenAI

OPENAI_API_KEY=... occ -m gpt-4o "hello"

# Google

GOOGLE_AI_API_KEY=... occ -m gemini-2.5-flash "hello"

# AWS Bedrock

AWS_ACCESS_KEY_ID=... AWS_SECRET_ACCESS_KEY=... occ -m bedrock/claude-sonnet "hello"

# Google Vertex

GOOGLE_APPLICATION_CREDENTIALS=... occ -m vertex/claude-sonnet "hello"

```

---

## 🔗 MCP Integration

Connect to MCP servers for additional tools:

```json

// .mcp.json

{

  "mcpServers": {

    "my-server": {

      "command": "npx",

      "args": ["-y", "my-mcp-server"],

      "env": { "API_KEY": "..." }

    }

  }

}

```

Supports 4 transports: stdio, SSE, Streamable HTTP, WebSocket.

---

## 🔍 Background: The Claude Code Source Leak

On March 31, 2026, Anthropic accidentally shipped source maps in the Claude Code npm package, [exposing the full TypeScript source](https://www.sabrina.dev/p/claude-code-source-leak-analysis). This project takes a different approach — we use [ruDevolution](https://github.com/ruvnet/rudevolution) to analyze the **published npm package** legally and rebuild from that intelligence.

### What ruDevolution Found

| Discovery | Evidence |

|-----------|---------|

| 🤖 Agent Teams | `CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS` |

| 🌙 Auto Dream Mode | `tengu_auto_dream_completed` |

| 🔮 claude-opus-4-6 | Unreleased model ID |

| 🔐 6 "amber" codenames | Internal feature gates |

| ☁️ Cloud Code Runner | BYOC compute |

| 📡 MCP Streamable HTTP | New transport |

[Download decompiled releases →](https://github.com/ruvnet/rudevolution/releases)

---

## ⚖️ Legal

This is a **clean-room implementation** — no leaked source used. Architecture informed by analysis of the published npm package, legal under US DMCA §1201(f), EU Software Directive Art. 6, UK CDPA §50B.

---

## 📚 Related

- [ruDevolution](https://github.com/ruvnet/rudevolution) — AI-Powered JavaScript Decompiler

- [Decompiled Releases](https://github.com/ruvnet/rudevolution/releases) — Every Claude Code version

- [v2 Architecture (ADR-001)](./docs/adr/ADR-001-v2-architecture.md)

- [Path to 100% (ADR-002)](./docs/adr/ADR-002-path-to-100-percent.md)

Nightly Release Pipeline

### Automated Nightly Verified Releases (ADR-001)

Open Claude Code includes an automated nightly CI/CD pipeline that:

1. **Detects** new Claude Code releases from npm registry (03:00 UTC daily)

2. **Verifies** compatibility with 903+ tests, npm audit, and smoke tests

3. **Analyzes** changes using Claude Sonnet 4.6 AI-powered discovery

4. **Publishes** verified releases with detailed notes — only if ALL gates pass

```

Cron 03:00 UTC → npm check → 903+ tests → npm audit → AI analysis → verified release

```

**Manual trigger:**

```bash

gh workflow run nightly.yml -f force_release=true

```

**Required secrets:**

- `GITHUB_TOKEN` — automatic

- `ANTHROPIC_API_KEY` — optional, for AI discovery analysis

See [ADR-001](docs/adr/ADR-001-nightly-verified-release-pipeline.md) for full architecture.

### rudevolution Integration

The [rudevolution](https://github.com/ruvnet/rudevolution) submodule provides AI-powered decompilation analysis of Claude Code releases, tracking 34,759+ functions with 95.7% name accuracy. Used by the nightly pipeline for change discovery.

## 📄 License

MIT