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An exe.dev box is a persistent Linux VM you reach over SSH. Paired with Ref, it works like a laptop that’s always on: Ref launches Claude Code on it from any ref, using your own login.

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Set up an exe.dev box

1

Create the box

Run ssh exe.dev and follow the prompts to sign up and choose a plan. Then create a box and connect:
If the short host form fails, use the username form: ssh vm+my-box@vm.exe.xyz.
2

Sign in to your agent

The default exeuntu image ships claude and codex preinstalled. Update Claude with sudo exeuntu update claude.Run claude and sign in with your Claude subscription (open the printed URL on your own computer). For Codex over SSH, run codex login --device-auth (beta; turn on device code login in your ChatGPT security settings first). Clone your repo onto the box.
Don’t use exe.dev’s LLM gateway (ANTHROPIC_BASE_URL=https://llm.int.exe.xyz) for Ref-driven runs. Ref clears ANTHROPIC_* variables when it starts Claude Code, so it uses your Claude Code sign-in.
1

Install Ref

Over SSH it prints a pairing URL: open it on your own computer and approve. With no terminal (scripts), set REF_API_KEY first. Needs claude or codex on PATH; Linux x86_64 and arm64 are supported.
2

Enable your repo

From the repo on the box:
This installs the systemd user unit ~/.config/systemd/user/ref-daemon.service and enables linger so it survives reboots. If it prints sudo loginctl enable-linger <user>, run that.If systemd isn’t available, re-running the installer restarts its keepalive after a reboot.
3

Check it

The box appears under Agent settings in Ref, named by its hostname. Ask a ref’s agent to launch a Task on it.
Codex and OpenCode over ACP are rolling out; today Ref drives Claude Code on paired machines for most accounts.

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Get help

If you have any issues, please reach out to help@ref.tools. We’re happy to help you get started!