How to use box by Simular with Codex
Add box by Simular to the Codex app, CLI or IDE extension with one MCP link. Codex gets a cloud Linux desktop with Chrome and a shell it can see and control.
box by Simular gives Codex a computer it can see and control. It is a cloud Linux desktop with Chrome, a shell and files, added to Codex as one remote MCP server. Codex can open websites, sign in, use desktop apps and check its work in a real browser.
What Codex can do with box
- Check the UI it just built. Codex opens your app in Chrome on the box, clicks through it and tells you what looks wrong.
- Reach web tools that have no API. Admin consoles and dashboards behind a login, using the browser session already signed in on the box.
- Share a desktop with your other agents. Start a job in Codex and let Claude Code or ChatGPT continue on the same box, with the same files.
Set up box in Codex
Follow the Quick Start, or add box by hand as in Codex app or Codex CLI in the MCP guide, which also cover signing in. One setup covers the Codex app, the CLI and the IDE extension.
Mention box as @box in your prompts so Codex doesn't pick a different app named Box.
Try these prompts
- "Use box to open <your app URL> in Chrome, sign up with a test email and tell me which step fails."
- "Use box to go to news.ycombinator.com and give me today's top 5 stories in a table."
- "Use box to open the admin panel I'm signed in to and download last month's invoices into ~/invoices."
What box adds to Codex
| Codex on its own | Codex + box by Simular | |
|---|---|---|
| Where it works | Your machine or its own environment | Plus a cloud desktop with Chrome, a shell and GUI apps |
| Logins | Whatever is signed in where Codex runs | Sign in once on the box and stay signed in |
| Other agents | Works alone | Claude, ChatGPT and others share the same box and pick up each other's work |
| Watching the work | Chat output | Live view; take control at any time |
FAQ
- Does one setup cover the Codex app, CLI and IDE? Yes. They share one config, so adding box once covers all three.
- Does box use my ChatGPT plan? Codex keeps using your own plan for its model. Model calls made by box's own tools use box credits.
- Is box the same as Codex cloud? No. box is a separate cloud desktop that Codex, and your other agents, can use through MCP.
Troubleshooting
box tools missing, or signed out? See Troubleshooting, or Codex app and Codex CLI in the MCP guide.
Read next
How to use box by Simular with Claude Code
Give Claude Code a cloud desktop with Chrome and a shell. One command adds box by Simular over MCP, so Claude Code can browse, sign in and test your app in a real browser.
How to use box by Simular with ChatGPT
Add box by Simular to ChatGPT as a custom MCP plugin. ChatGPT gets a cloud desktop with Chrome that stays signed in to your accounts. No terminal needed.