Codex CLI Setup

Learn how to configure Codex CLI to use Aiberm’s API. This guide covers installation and configuration for Windows, macOS, and Linux.

What is Codex CLI?

Codex CLI is OpenAI’s command-line interface designed for code-related terminal tasks. It emphasizes engineering-ready output with clearer, actionable code changes compared to general chat tools. By configuring it to use Aiberm, you can access multiple AI models through a cost-effective endpoint.

Prerequisites

Before you begin, ensure you have:

• An Aiberm account (Sign up here)
• An Aiberm API key (Get your key)
• Node.js v20 or higher with npm

Installation

Install Codex CLI globally using npm:

npm install -g @openai/codex

Verify installation:

codex --version

This should display the version number.

Configuration

Codex CLI uses a config.toml file for configuration. The config directory location varies by operating system:

• Windows: %userprofile%\.codex
• macOS/Linux: ~/.codex

Method 1: Manual Configuration

Navigate to the config directory and create or edit config.toml:

macOS/Linux:

mkdir -p ~/.codex
nano ~/.codex/config.toml

Windows:

mkdir $env:USERPROFILE\.codex -Force
notepad $env:USERPROFILE\.codex\config.toml

Add the following configuration:

model = "gpt-4"
model_reasoning_effort = "medium"
model_provider = "aiberm"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
env_key = "OPENAI_API_KEY"  # This refers to the environment variable name
wire_api = "responses"

Note: The env_key setting tells Codex CLI which environment variable to read. You’ll set your Aiberm API key in this variable in the next step.

Method 2: One-Command Configuration

macOS/Linux:

mkdir -p ~/.codex && cat > ~/.codex/config.toml << 'EOF'
model = "gpt-4"
model_reasoning_effort = "medium"
model_provider = "aiberm"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
env_key = "OPENAI_API_KEY"  # This refers to the environment variable name
wire_api = "responses"
EOF

Windows PowerShell:

$configPath = "$env:USERPROFILE\.codex"
New-Item -ItemType Directory -Force -Path $configPath | Out-Null
@"
model = "gpt-4"
model_reasoning_effort = "medium"
model_provider = "aiberm"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
env_key = "OPENAI_API_KEY"
wire_api = "responses"
"@ | Out-File -FilePath "$configPath\config.toml" -Encoding utf8

Note: The configuration above sets Codex CLI to read your API key from the OPENAI_API_KEY environment variable, which you’ll configure with your Aiberm API key in the next step.

Set API Key

After configuring the TOML file, set your Aiberm API key as an environment variable.

Important: Even though the variable is named OPENAI_API_KEY, you should use your Aiberm API key (not an OpenAI key). Codex CLI uses this standard variable name for compatibility.

Temporary (Current Session Only)

macOS/Linux:

export OPENAI_API_KEY="sk-your-aiberm-api-key"

Windows PowerShell:

$env:OPENAI_API_KEY="sk-your-aiberm-api-key"

Windows Command Prompt:

set OPENAI_API_KEY=sk-your-aiberm-api-key

Permanent Configuration

macOS/Linux (Bash):

Add to ~/.bashrc or ~/.bash_profile:

export OPENAI_API_KEY="sk-your-aiberm-api-key"

Apply changes:

source ~/.bashrc  # or source ~/.bash_profile

macOS/Linux (Zsh):

Add to ~/.zshrc:

export OPENAI_API_KEY="sk-your-aiberm-api-key"

Apply changes:

source ~/.zshrc

Windows PowerShell:

[System.Environment]::SetEnvironmentVariable('OPENAI_API_KEY', 'sk-your-aiberm-api-key', 'User')

Windows Command Prompt:

setx OPENAI_API_KEY "sk-your-aiberm-api-key"

Verify Configuration

Check Node.js installation:

node -v
npm -v

Verify Codex CLI installation:

codex --version

Test API connection:

codex "Hi"

Check environment variable:

macOS/Linux:

echo $OPENAI_API_KEY

Windows PowerShell:

echo $env:OPENAI_API_KEY

If configured correctly, Codex CLI should respond using Aiberm’s API.

Troubleshooting

401 Unauthorized Error

• Verify your API key is correct: Console → API Keys
• Ensure the OPENAI_API_KEY environment variable is set correctly
• Restart your terminal after setting environment variables

403 Forbidden Error

• Check your API key’s validity
• Verify your account balance at https://aiberm.com/console
• Ensure your API key has access to the requested model

Network Errors

• Verify your internet connection
• Check if you can access https://aiberm.com in your browser
• Ensure your firewall allows outbound HTTPS connections
• Confirm the base_url in config.toml is correct: https://aiberm.com/v1

Configuration Not Taking Effect

• Restart your terminal after editing config.toml
• Validate TOML syntax formatting (no extra spaces, proper quotes)
• Check the config file location is correct for your operating system
• Ensure the file is saved as config.toml (not config.toml.txt)

Codex Command Not Found

macOS/Linux:

# Check if npm global bin is in PATH
npm config get prefix

# If needed, add to PATH in ~/.zshrc or ~/.bashrc:
export PATH="$(npm config get prefix)/bin:$PATH"

Windows:

• Verify npm global path is in system PATH
• Restart terminal after npm installation