Codex Sandbox Skill

LIBRARY-FIRST PROTOCOL (MANDATORY)

Before writing ANY code, you MUST check:

Step 1: Library Catalog

• Location: .claude/library/catalog.json
• If match >70%: REUSE or ADAPT

Step 2: Patterns Guide

• Location: .claude/docs/inventories/LIBRARY-PATTERNS-GUIDE.md
• If pattern exists: FOLLOW documented approach

Step 3: Existing Projects

• Location: D:\Projects\*
• If found: EXTRACT and adapt

Decision Matrix

Purpose

Execute code in Codex’s fully isolated sandbox environment for safe experimentation with untrusted or risky code.

Unique Capability

What Claude Can’t Do: Claude runs in your environment. Codex sandbox provides:

• Network DISABLED: No external connections
• CWD only: Cannot access parent directories
• OS-level isolation: macOS Seatbelt or Docker
• Resource limits: CPU, memory constraints
• Safe experimentation: Can’t break your system

When to Use

Perfect For:

• Running untrusted code safely
• Risky refactoring experiments
• Testing code with potential bugs
• Isolated prototyping
• Security research
• Experimental dependencies

Don’t Use When:

• Need network access
• Need to access files outside project
• Production debugging

Usage

# Basic sandbox execution
/codex-sandbox "Refactor auth system and run tests"

# With iteration limit
/codex-sandbox "Fix all tests" --max-iterations 10

# Risky experiment
/codex-sandbox "Try experimental algorithm implementation"

CLI Command

codex --full-auto --sandbox true --network disabled "Your task"

# Via script
CODEX_MODE=sandbox bash scripts/multi-model/codex-yolo.sh "Task" "id" "." "10" "sandbox"

Isolation Layers

Integration Pattern

// 1. Run risky refactoring in sandbox
const result = await codexSandbox("Refactor entire auth system");

// 2. If successful, apply to real codebase
if (result.tests_pass) {
  Task("Coder", "Apply sandboxed changes to main", "coder");
}

Memory Integration

• Key: multi-model/codex/sandbox/{session_id}
• Contains: commands, files created/modified, test results