Install Codex on Windows
Install the ChatGPT desktop app, sign in with a work account, open a project folder and run a first task.
You have Codex running on your laptop, with a project folder open and a safe setting turned on.
You have the ChatGPT app installed, you are signed in to your work workspace, and Codex has completed a first task and a first approval in Documents\CodexWork.
You have a working Codex install on Windows with a project folder, the Ask for approval mode and one read-only task and one approved write behind you, and you know where admin policy and the sandbox type can change this.
What you are setting up
Codex is a part of the ChatGPT app on Windows. There is no second app to find.
You will install the app and sign in with your work account. Then you will make a folder and open it in Codex.
Last, you will pick the safest setting. With this setting, Codex asks you before it does anything that matters.
Since 9 July 2026, Codex is part of the ChatGPT desktop app on Windows. There is no separate Codex app to download.
You will sign in with your work Google account, choose your work workspace, and open one folder as the project. Codex works inside that folder.
You will also set the permission mode to Ask for approval. In this mode you see each action that needs approval before Codex does it.
On Windows, Codex ships inside the ChatGPT desktop app. The agent runs natively in PowerShell under the Windows sandbox, and WSL2 is optional. Windows 11 is the recommended base. Windows 10 version 1809 or later is best effort.
Sign-in uses a ChatGPT account. A work account can use Google sign-in if the workspace allows it. Workspace administrators can switch local Codex off, so a missing Codex entry is a policy question before it is an install fault.
The steps below fix three variables early: the project folder, which anchors the sandbox, the permission mode, and the network setting, which is off by default.
Install and sign in
Install the ChatGPT app
Open the Microsoft Store and search for ChatGPT. Check that the publisher is OpenAI. Select Get or Install.
Wait for the install to finish. Then open the app.
Microsoft Store
ChatGPT
Publisher: OpenAI
InstallStep 1. The Store page. Check the publisher name before you install. Sign in with your work Google account
In the app, select the sign-in option. Choose Continue with Google.
Pick your work Google account, not a personal one. Follow the prompts from your organisation.
Log in
Welcome back. Choose how you want to sign in.
Continue with GoogleContinue with emailStep 2. Choose Continue with Google, then pick the work account. Choose the work workspace
If the app asks which workspace to use, pick your work one.
Do not pick the personal one. Work files belong in the work workspace.
If the app asks which workspace to use, pick your work workspace, not Personal.
The workspace decides which Codex features you have and which terms apply to your files.
If you belong to more than one workspace, pick the work workspace, not Personal. Admin controls such as local Codex access, allowed models, allowed approval modes and blocked files attach to the workspace, as do the terms that cover file content sent to the model.
The picker wording in your app may differ from the illustration.
Choose a workspace
You belong to more than one workspace.
Work workspacePersonalStep 3. Pick the work workspace. Names on your screen will differ. Open Codex from the sidebar
Look in the sidebar of the app for Codex. Select it.
If you cannot find Codex, your admin may have turned it off. Ask your IT team.
Look in the app sidebar for Codex and select it.
If Codex is missing, the workspace admin may have turned off local Codex. Ask your IT team to check the setting called Allow members to use Codex locally.
Look in the app sidebar for Codex and select it.
If it is missing, check with the workspace admin. The setting Allow members to use Codex locally turns local Codex off for members. Use Codex in the cloud is a separate setting and is off by default on Enterprise.
New thread
Open a folder to start. Codex works inside the folder you choose.
Step 4. Codex with no project yet. Your sidebar may look different. Make the project folder
Open File Explorer. In Documents, make a folder called
CodexWork.Right-click the starter pack zip and choose Extract All. Set the destination to
Documents\CodexWork. You should see five folders andREADME.txtinsideCodexWork.- asset-manager
- business-analyst
- docker
- presentation
- procurement
- README.txt
Step 5. The starter pack unzipped inside CodexWork. Open the folder as the project
In Codex, choose the option to open a project folder. Select
Documents\CodexWork.The project name
CodexWorknow shows in the sidebar.New thread
I am ready to work in CodexWork. What would you like to do?
Step 6. The project CodexWork is open. Codex works inside this folder. Set the permission mode to Ask for approval
Find the mode setting under the message box. Open it.
Choose Ask for approval. Codex works inside your project folder. It stops and asks before it goes outside it, for example to use the internet.
Find the permission mode setting under the message box and open it. Choose Ask for approval.
The Codex docs recommend starting with this mode. Codex works inside the project folder and pauses before it reaches beyond it, for example to other files or the internet. Keep this mode for the whole course.
Open the permission mode menu under the message box and choose Ask for approval. In the CLI the command is
/permissions.The four modes sit on top of sandbox modes (
read-only,workspace-write,danger-full-access) and approval policies (on-request,never). A folder under git defaults to workspace-write with on-request. A folder without git defaults to read-only.New thread
I am ready to work in CodexWork. What would you like to do?
- ✓Ask for approval
- Approve for me
- Full access
- Custom
Step 7. The mode menu. Ask for approval is selected. Run a first read-only task
Paste the first prompt below into the message box and send it.
Codex reads the folder and answers. It should not change any file.
New thread
- List the folders in this project
List the folders in this project and describe what each one holds. Do not change any files.
The project holds five folders and a README: business-analyst, asset-manager, procurement, presentation and docker. Each holds sample files for one lab.
Step 8. Codex lists the folders and says what each holds. No file changes. Approve a first action
Paste the second prompt below and send it.
CodexWorkis not a git folder, so Codex asks before it creates a file.Read the card. Select Approve. Then open
CodexWorkin File Explorer and look forhello.txt.New thread
- List the folders in this project
- Create hello.txt
Create a file called hello.txt that says Hello from Codex.
I need your approval to create this file.
Codex wants to create a file in CodexWork.
ApproveDeclineStep 9. The approval card. Approve lets this one action run. Decline stops it.
List the folders in this project and describe what each one holds. Do not change any files.
This task only reads. Nothing in your folder changes.
A read-only request is the lowest-risk first test. If Codex asks for approval here, read the card before you decide.
Reading the file tree needs a shell listing, such as Get-ChildItem, which the sandbox allows inside the project. The prompt states the no-change constraint so the intent is explicit.
Create a file called hello.txt that says Hello from Codex.
Codex asks before it makes the file. Read the request, then approve or decline it.
In a folder without git, writing a file needs your approval. Approve only what you understand. You can decline and ask for a different approach.
A folder without git defaults to a read-only sandbox, so the write falls outside what the sandbox allows and raises an approval request. Each approval covers one action, not a standing grant.
| Mode | What Codex does without asking | Use it when |
|---|---|---|
| Ask for approval | Works inside the project folder. Asks before it reaches beyond it, for example to other files or the internet | You start, and for every lab in this course |
| Approve for me | Works inside the project folder. An automatic review handles routine requests, and Codex asks only about actions it detects as possibly unsafe | You know the task and the risks, after this course |
| Full access | Has unrestricted access to the internet and to any file on your computer | Never in this course. Follow your organisation's policy |
| Custom | Uses the permissions set in a configuration file, config.toml | You or your admin need rules that the other modes do not give |
Optional helpers
You can add three more programs later. You do not need them for the first labs.
Git for Windows saves versions of your files. Codex can also edit more freely inside a folder that uses git.
Python runs small programs that Codex writes. Labs B, C and D can use it, for example to read PDF files. Docker Desktop runs a mini computer for lab E.
Three programs are optional. Install each one only when a lab asks for it, and check your organisation's policy first.
Git for Windows keeps save points of your files. Codex also lets itself edit inside folders that use git. Python runs the scripts Codex writes for labs B, C and D, including reading PDF files. Docker Desktop is for lab E.
Ask Codex to tell you what it needs before you install anything.
Git for Windows gives you version history as an undo layer, and a git folder defaults to workspace-write with on-request approval, where a non-git folder defaults to read-only. Python runs generated scripts for labs B, C and D (PDF text extraction, analysis and slides), which makes results re-runnable. Docker Desktop (WSL2 backend) is for lab E.
WSL2 is optional for Codex itself and is enabled from Settings, followed by a restart.
Check the licence terms of Docker Desktop and your organisation's software policy before you install it on a work-related machine.
For scripted use and admins
Codex also has a version you use by typing commands in PowerShell. You do not need it for this course. Choose Advanced at the top to see how to install it.
IT teams can install the app from PowerShell, and workspace admins can set rules for every user. You do not need either for this course. Switch to Advanced to see the commands and the admin controls.
The app also installs from PowerShell: winget install --id 9PLM9XGG6VKS -s msstore. The CLI installs with powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex". There is no winget package for the CLI.
Windows sandbox types are MXC, which is recommended and needs Windows 11 24H2 or later, elevated, which needs admin setup, and unelevated.
Admins can enforce allowed approval modes, models, blocked files and network domains through managed configuration. The Codex docs are at learn.chatgpt.com/docs.
Key terms
- Workspace
Your organisation's space in ChatGPT.
Your organisation's ChatGPT account space.
The organisation-level ChatGPT tenant. Admin policy and data terms attach to it.
- Project folder
The folder you open in Codex. Codex works inside it.
The folder you open in Codex; the sandbox centres on it.
The folder you open in Codex. The sandbox centres on it, and Codex searches it for AGENTS.md.
- Permission mode
A setting that says when Codex must ask you first.
The Codex setting that decides what needs your approval.
A preset pairing of sandbox mode and approval policy: Ask for approval, Approve for me, Full access or Custom.
- Approval
Your yes or no to one thing Codex wants to do.
Your yes or no to one action Codex wants to take.
A human decision on a single proposed action, raised when the action falls outside the sandbox policy.
Check yourself
Why do you pick the work workspace and not Personal?
Work files belong with work rules. Your admin's rules only apply in the work workspace.
Your organisation's controls and data terms apply to the work workspace. Personal does not carry them.
Admin controls and the terms that cover file content sent to the model attach to the workspace, so the choice sets your policy and data position.
Which permission mode do you use for this course?
Ask for approval. Codex stops and asks before it does something that matters.
Ask for approval. It is the recommended start, and you see each action that needs approval.
Ask for approval, the recommended start. It keeps a human decision on each action that falls outside the sandbox policy.
Codex does not appear in the sidebar. What is the likely cause?
Your admin may have turned it off. Ask your IT team.
The workspace admin may have turned off local Codex. Ask IT to check the setting Allow members to use Codex locally.
Policy is the first suspect: Allow members to use Codex locally may be off for the workspace. Ask the admin before you troubleshoot the install.
OtterBlock is not affiliated with OpenAI. Codex and ChatGPT are OpenAI products.