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

Match	Action
Library >90%	REUSE directly
Library 70-90%	ADAPT minimally
Pattern exists	FOLLOW pattern
In project	EXTRACT
No match	BUILD (add to library after)

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

Layer	Protection
Network	DISABLED - no external connections
Filesystem	CWD only - no parent access
OS-Level	Seatbelt (macOS) / Docker
Process	Subprocess jail with limits
Commands	Blocked: rm -rf, sudo, etc.

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

codex-sandbox