rex-tty

Claude's Bash tool has no terminal, so sudo, gh auth login, a key passphrase or git rebase -i fail or hang there. Inside the Rex terminal, this mod runs those commands in a Rex pane beside the session. You type in the pane; Claude gets the exit code and what the pane showed.

┌ claude ───────────────────────────────────────────────┐
│ ● Bash(sudo make install)                             │
│   [rex-tty] waiting for you in pane tty-1             │
├ tty-1 ────────────────────────────────────────────────┤
│ rex-tty ▸ sudo make install                           │
│                                                       │
│ Password: ▌                                           │
└───────────────────────────────────────────────────────┘

What you type at a hidden prompt (a password, a passphrase) is never on screen, so it never reaches the model. Anything the pane does show, including input a command echoes back, is returned to Claude (see Limits).

What it does

• Bash commands that need a terminal go to a pane. The mod reads each Bash command before it runs. When it is one of the commands below, it opens a Rex split with the command, focuses it, waits for it to end, reads the pane and closes it. Claude receives that as the Bash tool's own result, with Exit code N added on a failure.
• tty_run tool. Claude can ask for a pane itself, for a command the list does not know. When a normal Bash command fails with a "no terminal" error (a terminal is required, not a tty, cannot prompt, …), the mod adds a note to the result that points Claude at this tool.
• Outside Rex it does nothing. Without REX_BLOCK in the environment, every command runs as usual and the tool is not registered.

Commands sent to a pane by default:

Plain ssh host is not on the list: with a key in the agent it works without a terminal. When it fails for lack of one, the note sends Claude to tty_run.

Permissions

A mod that answers a tool call runs before Claude Code's own permission dialog, so the mod asks first:

1. It queries the session's permission rules for the Bash command ($.tool.check).
2. Deny: the command is refused, as it would be without the mod.
3. Allowed by a rule you wrote (such as Bash(sudo:*)): the pane opens.
4. Anything else, including an allow that comes from the permission mode or from a sandbox's auto-allow: you are shown the whole command (up to 1,500 characters, control characters removed) and asked Run in a Rex pane / Run without a terminal / Do not run. Run without a terminal hands the command back to Claude Code, which then asks its usual permission question.

What this gate does not cover:

• The pane is outside Claude Code's Bash sandbox. A command you send to a pane runs with your full access, as it would in any terminal.
• PreToolUse hooks and the auto-mode classifier are not asked about a command that goes to a pane. The permission rules are, and so are other mods' tool.check hooks: a mod such as security/human-gate can still hold or deny it.
• tty_run is checked as the Bash command it carries, so Bash(...) rules apply to it. A rule written for mcp__rex-tty__tty_run itself is not what decides.

In a -p run with no allow rule there is no one to ask, and the command runs as it would without the mod.

Limits

• The pane's output goes to the model. A hidden prompt is safe, but everything the pane shows is read by Claude like any Bash output: a secret a command prints (gh auth token), a one-time code, and input a command echoes as you type it (a username, an access key ID at aws configure).
• Long output is cut to its end. Claude gets the last 30,000 characters of what the pane showed, with a line saying how much was left out. When the pane's text cannot be read, or is larger than 4 MiB, the result says so and the pane stays open. Set returnOutput to false to return only the exit code, or install security/secret-redactor below it.
• The pane has its own shell with your login environment (not your interactive config such as ~/.zshrc). It starts in the session's working directory, but variables Claude exported in earlier Bash commands, or a virtualenv it activated, are not set there.
• Interrupting the turn closes the pane, with whatever was running in it.
• A command that runs past timeoutMinutes is not stopped. Claude is told it is still waiting in the pane, and the pane stays open.
• run_in_background commands are never sent to a pane.
• The command detection reads the command line as words. It does not see inside bash -c '…', a script file, an alias or xargs, and it sends sudo even when your sudoers needs no password; commands adds your own patterns and tty_run covers the rest.

Options

  commands: string         extra regex sources, comma-separated: a matching Bash command also goes to a pane
  skip: string             regex sources, comma-separated: a matching Bash command always runs as usual
  side: string             below | right | above | left (default below)
  ratio: number            percent of the split the pane takes, 10-90 (default 35)
  closeOnExit: boolean     close the pane when the command ends (default true)
  returnOutput: boolean    give Claude the pane's output; false returns only the exit code (default true)
  timeoutMinutes: number   how long to wait for the command, 1-720 (default 30)

Install

npx claude-code-templates@latest --mod integrations/rex-tty
claude

It is written to .claude/skills/rex-tty/, which Claude Code auto-loads as rex-tty@skills-dir once the workspace trust prompt is accepted. For one session: claude --plugin-dir .claude/skills/rex-tty. claude plugin validate .claude/skills/rex-tty prints every event it hooks and every $ call it makes; claude plugin test .claude/skills/rex-tty runs its tests.

Options are read from user settings (~/.claude/settings.json, never project settings), --settings <file> or managed settings, under the plugin's full id:

{
  "pluginConfigs": {
    "rex-tty@skills-dir": {
      "options": { "side": "right", "ratio": 40, "commands": "^terraform (apply|destroy)\\b" }
    }
  }
}

With --plugin-dir the key is rex-tty.

Requirements

• Claude Code >= 2.1.316, started inside a Rex terminal (Rex sets REX_BLOCK and REX_BIN_DIR).
• The rex CLI of Rex 0.0.1793981048 or later. Rex is in beta: the mod uses rex split --json, rex wait --json, rex capture and rex block close|focus, and a later Rex may change them.

Environment variables it reads: REX_BLOCK, REX_BIN_DIR, SHELL. The rex binary it runs is $REX_BIN_DIR/rex and the pane's shell is $SHELL (bash, zsh, sh, dash or ksh; otherwise /bin/bash), so both follow the environment Claude Code was started with. It makes no network request and stores nothing.