vagejs with OpenAI Codex
AGENTS.md, read natively.
Codex is OpenAI's coding agent. You can run it in a terminal (the Codex CLI), inside your editor, or in the cloud from ChatGPT. Codex was one of the first tools to adopt AGENTS.md, the file every vagejs site ships with, so there's nothing to configure.
Set up the CLI
npm install -g @openai/codex
npm create vagejs@latest my-site
cd my-site && npm install
codexHomebrew users can run brew install --cask codex instead. The Codex repository lists every install option.
How Codex reads the instructions
When it starts, the Codex CLI reads a global AGENTS.md from ~/.codex/, then the AGENTS.md files from your project root down to the folder you're working in. The vagejs instructions sit at the root, so they always load. Codex caps the combined size (32 KiB by default), and the vagejs file is well under it. Details are in OpenAI's AGENTS.md guide.
Choose an approval mode
Type /permissions in a session to pick how much Codex may do without asking. Start with a mode that asks before running commands, and loosen it once you trust the setup. Avoid Full access (--yolo) on a real project. OpenAI's approvals guide explains each mode.
vagejs adds its own safety net: vage deploy and deploy:github stop and show their plan, so Codex can't publish unless you confirm.
In your editor and in the cloud
- IDE extension: install the Codex extension from the VS Code Marketplace (it also works in Cursor). Open your site's folder and chat with it in the sidebar.
- Codex cloud: connect the GitHub repository, and set the environment's setup script to
npm ciso the checks can run. Codex then works on its own copy of your repo, and you review its changes before they reach your site.
Prompts to try
Follow AGENTS.md. Rename /services/ to /what-we-do/, add the redirect, update every link, then run npx vage check --json until it reports 0 errors.Add a page for each item in team.md under src/pages/team/. Use only the facts in the file. List any missing details instead of guessing.Explain what npx vage audit found on the home page and fix the size problems without changing how the page looks.See the prompt library for more.
Good to know
- Want a rule only for one folder, such as the blog? Add an
AGENTS.mdinsidesrc/pages/blog/. Codex reads it along with the root file when it works in that folder. AGENTS.override.mdin a folder replaces that folder'sAGENTS.md. Use it sparingly, so the vagejs rules don't get lost.