OpenAI Codex
Let an AI coding agent inspect a project, explain it, and make a small reversible change.
- Suitable for
- People who already use AI chat and want to understand what an agent can do inside a real folder.
- Do not start here if
- Do not start with confidential work, production systems, or files without a backup.
- Visible result
- A visible file diff plus a plain-language explanation of what changed and how to undo it.
- Time
- 60 min
- Device
- A macOS, Windows, or Linux computer
- Account
- An account or API access accepted by the current official Codex setup
- Cost
- Usage cost may depend on the account and plan; verify before starting
- Data
- A disposable sample folder with no secrets
- HAACC check
- Editorially reviewed
Not run by HAACC
Before you start
A macOS, Windows, or Linux computer
An account or API access accepted by the current official Codex setup
Usage cost may depend on the account and plan; verify before starting
A disposable sample folder with no secrets
No programming knowledge required; reading file changes helps
The path
- 01
Choose a safe first task
Create a new sample folder. Put one short text or README file inside it. Do not use work files, credentials, personal data, or a production repository.
Continue only whenYou can delete the entire folder without losing anything important. - 02
Use the current official setup
Open the source link below and follow its current installation and sign-in path for your operating system. Do not paste commands copied from comments or third-party videos.
Continue only whenCodex opens and can see only the sample folder you selected. - 03
Ask for an explanation first
Ask Codex to describe the files, identify uncertainty, and propose one tiny change. Tell it not to edit until you approve the plan.
Continue only whenIts answer names the target file and describes a reversible change. - 04
Approve one change and inspect the diff
Approve only the small change. Read the resulting diff before accepting anything else. Ask Codex to explain how to undo it, then try the undo if this is your first run.
Continue only whenYou can point to the exact changed lines and restore the original file.
The sample file changes exactly as approved, the diff is visible, and the original can be restored.
Evidence boundary
HAACC reviewed the public source and shaped this path, but did not run the project on a clean machine. Treat every install step as unverified.
What HAACC checked
- Repository identity, public metadata, declared Apache-2.0 license, and editorial purpose
- A low-risk first-use sequence that starts in a disposable folder
What remains unchecked
- Installation, login, model behavior, billing, and removal on any operating system
- The repository revision was not pinned in this editorial snapshot
Stop and read
Never expose secrets
Do not place API keys, passwords, private keys, client data, or confidential files inside the trial folder.
An agent can change files
Read every proposed change and keep a backup. A plausible explanation is not proof that a change is correct.
When something fails
Sign-in or access is rejected
Stop and check the official account and regional availability notes. Do not buy or share credentials through a third party.
The agent asks to access more files than expected
Deny the request, close the session, and restart with only the disposable folder in scope.
Close Codex, remove the sample folder if no longer needed, uninstall through the official method, and revoke any token you created for this trial.
Turn it into your project
Personal document maintainer
Turn one repeated document cleanup task into a reusable prompt and checklist.
Change explanation page
Publish before/after evidence and the exact boundary of what was not checked.
Source snapshot
- Repository
- openai/codex
- Captured
- 2026-07-20
- Stars at capture
- 99,623
- Forks at capture
- 14,913
- GitHub license field
- Apache-2.0
- Pinned revision
- Not pinned