Install an agent on a host

simstim installs an agent with its vendor’s own installer, in a session on the host, so you see the installer’s output and can answer its questions. Then you log in with the agent’s own login, in a session. simstim never logs in for you, and never sees your login.

Pick them from a checklist

simstim setup ends with a checklist of every agent it can install. First-class and supported agents come first; best-effort ones follow, marked as such. The agents the host has are ticked already, with their state: installed, logged in, or not.

   1  [x] Claude Code      installed, logged in
   2  [ ] Codex            not installed
   3  [ ] opencode         not installed
   4  [ ] Antigravity CLI  not installed
  Best effort, kept working by contributors:
   5  [ ] Gemini CLI       not installed

Type the numbers of the agents to install, such as 2 3. The setup installs them one after another, each in its own session that you watch, as agents install does below. Then, for each agent that is not logged in, it offers the agent’s own login in a session. When you leave a session, by detaching or when it ends, the setup checks the host again and says how it went.

• On a host you have already set up, run simstim setup --host my-server.
• host add shows the same checklist, in a terminal, when a first-class or supported agent is missing.
• In the launcher, the add-host wizard shows it after “ready”, and s opens the whole setup.
• For a script, name the agents: simstim setup --host my-server --agents claude,codex --yes. Without a terminal, the setup waits for each installer to end, and leaves the logins to you.

Install one agent

simstim agents install claude --host my-server

The client:

1. Checks the host. If the agent is already installed, it says where and stops; --force runs the installer again, for example to update the agent.
2. Prints the install command and the vendor page it comes from.
3. Starts a session named install-claude that runs the command, and attaches to it. Answer the installer’s questions there. Detach with ctrl+\ at any time; the installer keeps running, and simstim attach my-server/install-claude brings you back.
4. When the installer ends, checks the host again and says how to log in.

With one host, --host is not needed. simstim agents ls lists every agent and its install command, and the agent reference lists each command’s source.

Log in

Each agent logs in its own way. Run its login in a session, and follow its prompts: most print a link to open in your browser and ask for the code it shows.

simstim new my-server -- claude auth login
simstim new my-server -- codex login --device-auth

For an agent whose first start is its login, such as Antigravity CLI, start the agent: simstim new my-server --agent antigravity.

An agent that takes an API key instead, such as Aider, can get it from your laptop at the start of each session: see pass secrets to a session.

Check the agents

host add and host doctor check each first-class and supported agent, and any other agent that is installed:

simstim host doctor my-server

Agents:
  ✓ Claude Code      /home/me/.local/bin/claude, logged in (`claude auth status` says so)
  ! Codex            /home/me/.local/bin/codex, not logged in (`codex login status` says not)
    Try: simstim new my-server -- codex login --device-auth
  ✕ opencode         /home/me/.opencode/bin/opencode is not on PATH in a login shell
    Try: on the host, add it to PATH: echo 'export PATH="/home/me/.opencode/bin:$PATH"' >> ~/.profile
  ? Antigravity CLI  /home/me/.local/bin/agy, login unknown (the agent has no status command or credentials file to read)

Sessions find agents through your login shell, the way ssh my-server does. An agent the installer put in a folder that is not on PATH there, such as ~/.local/bin on some systems, is installed but cannot start: add the folder to PATH in ~/.profile on the host.

The host decides “logged in” from the agent’s own signs, kept as data in the agent table: a variable such as ANTHROPIC_API_KEY set in the login shell, the agent’s own status command (claude auth status, codex login status), or its credentials file. It reads no file’s content and shows no command’s output.