Can't enter alternate screen buffer

What version of Codex CLI is running?

codex-cli 0.133.0

What subscription do you have?

gpt-5.5

Which model were you using?

gpt-5.5

What platform is your computer?

Linux 6.19.10-300.fc44.x86_64 x86_64 unknown

What terminal emulator and version are you using (if applicable)?

screen/tmux

Codex doctor report

What issue are you seeing?

Subject

TUI fails to enter Alternate Screen Buffer when tui.alternate_screen = "always" on Linux/Fedora

Describe the Bug

Even when tui.alternate_screen is explicitly set to "always" in ~/.codex/config.toml (or passed via CLI overrides), Codex CLI (v0.133.0) fails to transition to the terminal's alternate screen buffer.

Instead of taking over the viewport in a clean, full-screen mode (like vim), the TUI continues to render inline directly within the primary screen buffer (main scrollback). Upon exiting the CLI (via /exit or Ctrl+C), the welcome banner, help prompts, and interactive history are not cleared and remain permanently in the terminal's scrollback history, polluting the shell.

Environment

• Codex CLI Version: v0.133.0
• Operating System: Fedora Linux (Workstation)
• Terminal Emulator: [Please insert your terminal name here, e.g., GNOME Terminal, Alacritty, iTerm2]
• TERM Variable: xterm-256color / xterm

Steps to Reproduce

1. Configure ~/.codex/config.toml with the following:

```toml
[tui]
alternate_screen = "always"

What steps can reproduce the bug?

start codex-cli

What is the expected behavior?

_No response_

Additional information

_No response_