Name: open-claude-code
Author: ruvnet

Installation

Add to your Claude Code skills directory:

# Add to your Claude Code skills
git clone https://github.com/ruvnet/open-claude-code

Security Report

Verified

Last scanned: —

{
  "status": "PASSED",
  "issues": []
}

README.md

Automated Nightly Releases — Open Claude Code automatically detects new Claude Code releases, runs 903+ tests to verify zero regressions, and publishes verified builds with AI-powered discovery analysis. See Releases | ADR-001 | pi.ruv.io

⚡ Quick Start

# 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.

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, informed by ruDevolution's 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)

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

Global install

npm install -g @ruvnet/open-claude-code
occ "your prompt here"

From source

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

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

occ
# > explain this codebase
# > /help
# > /tools
# > /model claude-opus-4-6
# > refactor the database layer
# > /cost
# > /exit

CLI Options

occ [options] [prompt]

Options:
  -m, --model &#x3C;model>          Model to use (default: claude-sonnet-4-6)
  -p, --print                  Print mode (non-interactive, output only)
  --permission-mode &#x3C;mode>     Permission mode: default, auto, plan, acceptEdits, 
                               bypassPermissions, dontAsk
  --system-prompt &#x3C;text>       Override system prompt
  --add-dir &#x3C;path>             Additional CLAUDE.md directory
  --max-turns &#x3C;n>              Maximum conversation turns
  --allowedTools &#x3C;tools>       Comma-separated allowed tools
  --disallowedTools &#x3C;tools>    Comma-separated denied tools
  --output-format &#x3C;fmt>        Output: text, json, stream-json
  -v, --verbose                Verbose output
  -d, --debug                  Debug mode
  --version                    Show version
  -h, --help                   Show help

Examples

# 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 <name> 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 <level> 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:

{
  "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):

.claude/settings.local.json (local, gitignored)
.claude/settings.json (project, shared)
~/.claude/settings.json (user global)
Managed policy (enterprise)

CLAUDE.md

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

# 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:

---
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:

---
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:

# 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:

// .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. This project takes a different approach — we use 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 →

⚖️ 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 — AI-Powered JavaScript Decompiler
Decompiled Releases — Every Claude Code vers

Frequently Asked Questions

What is open-claude-code?⌄

open-claude-code is an open-source cli tools skill for AI coding assistants such as Claude Code, Codex CLI, and ChatGPT, built by ruvnet. Nightly Claude Code CLI Decompile — Reverse Engineered & Rebuilt. It has 480 GitHub stars.

Is open-claude-code safe to use?⌄

Yes. open-claude-code passed SkillsLLM's automated security scan — a dependency vulnerability audit plus prompt-injection heuristics — with no high-severity issues. You can read the full report in the Security Report section on this page.

How do I install open-claude-code?⌄

Clone the repository with "git clone https://github.com/ruvnet/open-claude-code" and add it to your Claude Code skills directory (see the Installation section above).

What programming language is open-claude-code written in?⌄

open-claude-code is primarily written in JavaScript. It is open-source under ruvnet on GitHub, so you can review or fork the full source.

Are there alternatives to open-claude-code?⌄

Yes. SkillsLLM lists many other CLI Tools skills you can browse and compare side by side. Open the CLI Tools category from the badge at the top of this page, or use the Related Skills and comparison links further down to weigh open-claude-code against similar tools.

open-claude-code