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Codex CLI Setup Guide

This guide will walk you through the setup of Codex CLI on your CNH machine. We currently support:

  • Windows 10+
  • Windows Subsystem for Linux (WSL/WSL2) w/ Ubuntu
  • macOS

Prerequisites

  • Node.js*
  • npm*
  • Python 3.12+*
  • Our Python authentication script <-- Download script and save to your computer
  • You must be part of an approved user group, such as EDP_Developer_AIMLCollaborators or a lab group that has an Azure AD entry

*May require admin approval

Installation

1. Set up Codex CLI executable

In a terminal window:

npm install -g @openai/codex

You can also install Codex from official distribution platforms such as brew in macOS and the official shell script for WSL.

2. Install the authentication dependency

python -m pip install --user msal msal-extensions

sudo apt install python3-msal python3-msal-extensions gir1.2-secret-1 wslu -y

python3 -m pip install --user msal msal-extensions

3. Create the MSAL Authentication Script

Download the Python script and save it to a known location.

Link to Script

We suggest the following paths to store the file:

C:\Tools\cnh-token.py

/home/<username>/Tools/cnh-token.py

/Users/<username>/Tools/cnh-token.py

4. Configure Codex

Create a folder for Codex in your home directory if it does not already exist.

Windows: C:\Users\<username>\.codex
WSL: ~/.codex
Mac: /Users/<username>/.codex

Here, you will need to create a file called config.toml that controls some of the underlying behavior of Codex. Use one of the following options. For all options, if you changed where the authentication script is stored, remember to change the path under the [model_providers.azure.auth] block.

In C:\Users\<username>\.codex\config.toml: 

model = "gpt-5.6-terra"
model_provider = "azure"
model_reasoning_effort = "medium"
approval_policy = "on-request"
sandbox_mode = "workspace-write"

[model_providers.azure]
name = "Azure OpenAI"
base_url = "https://aiml-apim-dev.azure-api.net/ai/coding-assistants/codex"
wire_api = "responses"
request_max_retries = 0
stream_max_retries = 0

[model_providers.azure.auth]
command = "python"
args = [
    "C:\\Tools\\cnh-token.py"
]
timeout_ms = 120000

[profiles.fast]
model = "gpt-5.6-luna"
model_reasoning_effort = "low"

[profiles.balanced]
model = "gpt-5.6-terra"
model_reasoning_effort = "medium"

[profiles.deep]
model = "gpt-5.6-sol"
model_reasoning_effort = "high"

[windows]
sandbox = "elevated"

In ~/.codex/config.toml: 

model = "gpt-5.6-terra"
model_provider = "azure"
model_reasoning_effort = "medium"
approval_policy = "on-request"
sandbox_mode = "workspace-write"

[model_providers.azure]
name = "Azure OpenAI"
base_url = "https://aiml-apim-dev.azure-api.net/ai/coding-assistants/codex"
wire_api = "responses"
request_max_retries = 0
stream_max_retries = 0

[model_providers.azure.auth]
command = "python3"
args = [
    "/home/<username>/Tools/cnh-token.py"
]
timeout_ms = 120000

[profiles.fast]
model = "gpt-5.6-luna"
model_reasoning_effort = "low"

[profiles.balanced]
model = "gpt-5.6-terra"
model_reasoning_effort = "medium"

[profiles.deep]
model = "gpt-5.6-sol"
model_reasoning_effort = "high"

In /Users/<username>/.codex/config.toml: 

model = "gpt-5.6-terra"
model_provider = "azure"
model_reasoning_effort = "medium"
approval_policy = "on-request"
sandbox_mode = "workspace-write"

[model_providers.azure]
name = "Azure OpenAI"
base_url = "https://aiml-apim-dev.azure-api.net/ai/coding-assistants/codex"
wire_api = "responses"
request_max_retries = 0
stream_max_retries = 0

[model_providers.azure.auth]
command = "python3"
args = [
    "/Users/<username>/Tools/cnh-token.py"
]
timeout_ms = 120000

[profiles.fast]
model = "gpt-5.6-luna"
model_reasoning_effort = "low"

[profiles.balanced]
model = "gpt-5.6-terra"
model_reasoning_effort = "medium"

[profiles.deep]
model = "gpt-5.6-sol"
model_reasoning_effort = "high"

5. Start Codex

Open a new terminal window and start Codex CLI:

codex

Codex will open a window for you to sign in with your Microsoft credentials. Once you've signed in, the token should be good for a while.

Agents and Skills

For details on AGENTS.md, custom agents, and skills, see Agents and Skills for Codex.

MCP Servers

For details on MCP servers and Codex configuration, see MCP Servers for Codex.

Happy coding!