OpenAI Codex CLI Setup Guide

Overview

OpenAI Codex CLI is OpenAI’s official command-line programming assistant. By configuring LaoZhang API, you can:

🚀 Stable Service

OpenAI-compatible endpoint

💰 Flexible Billing

Pay-per-use or per-request

⚡ GPT-5 Support

Access latest GPT-5 models

🔧 Simple Setup

Complete configuration in minutes

Prerequisites

Required Software

Install Git

Download from Git website

Windows: Use default installation settings
macOS: Usually pre-installed

Install Node.js

Download from Node.js websiteRequires Node.js 22 or higher

Verify Installation

Open terminal and verify:

git --version
node --version
npm --version

Install Codex CLI

Option 1: npm Install

npm install -g @openai/codex

Option 2: Source Install

git clone https://github.com/openai/codex.git
cd codex
npm install
npm link

Configure LaoZhang API

1. Get API Key

Visit LaoZhang API Console
Create a new token
Copy the key

2. Set Environment Variables

macOS/Linux
Windows

Edit ~/.zshrc or ~/.bashrc:

# LaoZhang API Configuration
export OPENAI_API_KEY="sk-your-laozhang-api-key"
export OPENAI_BASE_URL="https://api2.laozhang.ai/v1"

Apply changes:

source ~/.zshrc

Edit PowerShell profile:

notepad $PROFILE

# Add these lines
$env:OPENAI_API_KEY = "sk-your-laozhang-api-key"
$env:OPENAI_BASE_URL = "https://api2.laozhang.ai/v1"

Restart PowerShell or run:

. $PROFILE

3. Verify Configuration

echo $OPENAI_API_KEY
echo $OPENAI_BASE_URL

# Start Codex
codex

Usage Guide

Basic Usage

cd ~/my-project
codex

# Or ask directly
codex "Create an Express server"

Interactive Mode

> Please optimize this function's performance
> Add unit tests to the project
> Explain this code's logic

Common Commands

Command	Function
`codex`	Start interactive mode
`codex "question"`	Ask directly
`codex --model gpt-5`	Specify model
`codex --help`	Show help

Model Selection

Available models through LaoZhang API:

Model	Model ID	Features	Recommended For
GPT-5	`gpt-5`	Latest & strongest	Complex tasks
GPT-4.1	`gpt-4.1`	Fast & capable	Daily development
GPT-4.1 Mini	`gpt-4.1-mini`	Lightweight	Simple tasks
o4-mini	`o4-mini`	Enhanced reasoning	Algorithm problems

Switch Models

codex --model gpt-5 "Optimize this code"
codex --model o4-mini "Solve this algorithm problem"

Supported Features

✅ Code generation and completion
✅ Bug fixing and debugging
✅ Code refactoring
✅ Documentation generation
✅ Test case writing
✅ Code explanation
✅ Multi-language support

Supported Languages

Python, JavaScript/TypeScript, Java, C++, C#, Go, Rust, Swift, Kotlin, Ruby, PHP, HTML/CSS, SQL, Shell Scripts, and all major programming languages.

Troubleshooting

Connection Timeout or Failed

Check configuration:

Environment variables are set correctly
API key is valid
Network connection is stable

curl https://api2.laozhang.ai/v1/models \
  -H "Authorization: Bearer $OPENAI_API_KEY"

Invalid API Key

Ensure you’re using a LaoZhang API key:

Visit LaoZhang API Console
Check if key is valid
Verify account balance

Model Unavailable

Some models may be temporarily unavailable:

codex --model gpt-4.1 "your question"

How to Update Codex

npm update -g @openai/codex

Best Practices

Effective Prompts

✅ Good prompts:
"Create a Python function that parses JSON and returns data sorted by date"
"Refactor this class using singleton pattern"
"Add error handling and retry mechanism to this API"

❌ Avoid vague:
"Write code"
"Fix bug"

Performance Tips

Be specific: Clear descriptions reduce round trips
Provide context: Tell AI about tech stack and constraints
Break down tasks: Split complex tasks into smaller steps
Batch related tasks: Describe related tasks together

Cost Control

Billed by token usage
Use gpt-4.1-mini for simple tasks
Check Pricing page for details

Tool Comparison

Tool	Type	Advantages	Best For
Codex CLI	CLI	GPT-5 support, lightweight	Terminal users
Claude Code	CLI	Strong Agent mode	Complex refactoring
Cursor	IDE	Friendly UI	Daily development
Cline	VS Code	Full Agent	VS Code users

OpenAI Codex

Learn about Codex technology

API Console

Manage API keys and usage

Claude Code

Claude programming assistant

Model Comparison

View all coding model comparisons

Need help? Visit LaoZhang API for support.

Programming

Overview

Conversational AI

Engineering

Translation

OpenAI Codex CLI Setup Guide

Overview

🚀 Stable Service

💰 Flexible Billing

⚡ GPT-5 Support

🔧 Simple Setup

Prerequisites

Required Software

Install Codex CLI

Option 1: npm Install

Option 2: Source Install

Configure LaoZhang API

1. Get API Key

2. Set Environment Variables

3. Verify Configuration

Usage Guide

Basic Usage

Interactive Mode

Common Commands

Model Selection

Switch Models

Supported Features

Supported Languages

Troubleshooting

Best Practices

Effective Prompts

Performance Tips

Cost Control

Tool Comparison

OpenAI Codex

API Console

Claude Code

Model Comparison

​Overview

🚀 Stable Service

💰 Flexible Billing

⚡ GPT-5 Support

🔧 Simple Setup

​Prerequisites

​Required Software

​Install Codex CLI

​Option 1: npm Install

​Option 2: Source Install

​Configure LaoZhang API

​1. Get API Key

​2. Set Environment Variables

​3. Verify Configuration

​Usage Guide

​Basic Usage

​Interactive Mode

​Common Commands

​Model Selection

​Switch Models

​Supported Features

​Supported Languages

​Troubleshooting

​Best Practices

​Effective Prompts

​Performance Tips

​Cost Control

​Tool Comparison

​Related Resources

OpenAI Codex

API Console

Claude Code

Model Comparison

Overview

Prerequisites

Required Software

Install Codex CLI

Option 1: npm Install

Option 2: Source Install

Configure LaoZhang API

1. Get API Key

2. Set Environment Variables

3. Verify Configuration

Usage Guide

Basic Usage

Interactive Mode

Common Commands

Model Selection

Switch Models

Supported Features

Supported Languages

Troubleshooting

Best Practices

Effective Prompts

Performance Tips

Cost Control

Tool Comparison

Related Resources