Overview
What Link Host is, what it does on your computer, and how the Link app reaches it.
Link turns your Android phone into a control surface for your own computer: chat with the coding agents running there, open its terminals, browse its files and see its screen. Link Host is the small program that makes the computer reachable. You install it once, scan a code with the app, and walk away from your desk.
$curl -fsSL https://link.docs.razin.ai/install.sh | shWhat it does
Link Host is one binary, link-host, installed for your account only. It never needs administrator rights on Linux, and it never asks you to change your router or firewall.
- Runs a private SSH server for your phone (Linux): the system's own OpenSSH, started as you on port 2222, that accepts only the keys of phones you paired. Passwords are refused.
- Pairs phones with a one-time QR code. The phone makes its own key; the code only lets it add that key, once, within ten minutes.
- Keeps the computer findable from anywhere with outgoing connections only: directly when the phone can reach it, through a direct path it opens when they are on different networks, or through a relay you deploy when nothing else works. See How the phone connects.
- Streams the desktop on Linux, started on demand by the phone and tunnelled inside SSH.
- Relays Claude Code prompts from sessions you started in a terminal, so you can answer them from the phone (Claude in a terminal).
One connection carries everything
The app opens one SSH connection per computer. Inside it, each feature gets its own channel:
| Feature | Inside the SSH connection |
|---|---|
| Agents | One process per agent (claude, codex, opencode, gemini, pi, crush), talking its own protocol |
| Terminals | A PTY attached to a tmux session, which outlives the phone |
| Files | SFTP, the file protocol built into SSH |
| Desktop | A port forward to a stream that only listens on the computer's loopback |
Your agent logins, API keys and code never leave the computer. The phone sends what you type and receives what the agents say.
Where to start
Install Link Host
One command on Linux, macOS or Windows.
Pair your phone
Scan the QR code the installer prints.
Agents
Which agents work, approvals, permission modes, undo.
Commands
Every link-host command and option.
What's ready today
Linux is the complete platform: pairing by QR code, every connection mode, and the desktop. On macOS and Windows, Link Host installs and runs, and the phone connects through the system's own SSH server with your account password, on networks where it can reach the computer. See macOS and Windows.