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-5.6-sol"
model_provider = "aiberm"
model_reasoning_effort = "xhigh"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
experimental_bearer_token = "sk-your-aiberm-api-key"
wire_api = "responses"
supports_websockets = false

Important: Replace sk-your-aiberm-api-key with the real API key created in Aiberm Console. Do not leave the example placeholder unchanged.

The API key is stored as plain text in config.toml on this computer. Do not commit this file to Git, upload it publicly, or share it with anyone else.

Method 2: One-Command Configuration

macOS/Linux:

mkdir -p ~/.codex && cat > ~/.codex/config.toml << 'EOF'
model = "gpt-5.6-sol"
model_provider = "aiberm"
model_reasoning_effort = "xhigh"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
experimental_bearer_token = "sk-your-aiberm-api-key"
wire_api = "responses"
supports_websockets = false
EOF

Windows PowerShell:

$configPath = "$env:USERPROFILE\.codex"
New-Item -ItemType Directory -Force -Path $configPath | Out-Null
@"
model = "gpt-5.6-sol"
model_provider = "aiberm"
model_reasoning_effort = "xhigh"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
experimental_bearer_token = "sk-your-aiberm-api-key"
wire_api = "responses"
supports_websockets = false
"@ | Out-File -FilePath "$configPath\config.toml" -Encoding utf8

Before running either one-command setup, replace sk-your-aiberm-api-key in the command with your real API key. The generated configuration will not work if the placeholder is left unchanged.

Verify Configuration

Check Node.js installation:

node -v
npm -v

Verify Codex CLI installation:

codex --version

Test API connection:

codex "Hi"

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

Troubleshooting

401 Unauthorized Error

• Verify your API key is correct: Console → API Keys
• Confirm experimental_bearer_token contains the complete API key
• Confirm the placeholder sk-your-aiberm-api-key was not saved unchanged
• Restart Codex CLI after saving config.toml

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)
• Make sure each setting is on its own line
• 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