Regression: VS Code sendSequence Shift+Enter workaround no longer inserts newline

What version of Codex CLI is running?

codex-cli 0.128.0

What subscription do you have?

Not subscription-specific; this is a TUI terminal input handling issue.

Which model were you using?

Not model-specific.

What platform is your computer?

Darwin 25.4.0 arm64 arm

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

VS Code integrated terminal:

• VS Code 1.119.0
• Commit 8b640eef5a6c6089c029249d48efa5c99adf7d51
• TERM_PROGRAM=vscode
• TERM=xterm-256color
• No tmux/zellij/screen involved

What issue are you seeing?

A VS Code integrated terminal keybinding that previously let Shift+Enter insert a newline in the Codex TUI no longer works on the latest published CLI version, 0.128.0.

The keybinding sends ESC + LF to the terminal:

{
  "key": "shift+enter",
  "command": "workbench.action.terminal.sendSequence",
  "args": { "text": "\^[\u000A" },
  "when": "terminalFocus"
}

Previously, pressing Shift+Enter with this VS Code binding inserted a newline in the composer. Now it no longer inserts a newline.

What steps can reproduce the bug?

1. Add this keybinding to VS Code keybindings.json:

``json
{
"key": "shift+enter",
"command": "workbench.action.terminal.sendSequence",
"args": { "text": "\^[\u000A" },
"when": "terminalFocus"
}
``

1. Open the VS Code integrated terminal.
2. Run codex.
3. Type text in the composer.
4. Press Shift+Enter.

What is the expected behavior?

The ESC + LF sequence sent by VS Code should be treated as a modified Enter / newline insertion sequence, so Shift+Enter inserts a newline in the composer instead of failing to create a new line.

Additional information

This looks related to the recent TUI keymap/input handling regressions around modified Enter sequences:

• #20501
• #20555
• #20580

It may also be related to the C0 normalization work in #20798, which appears merged but is not yet included in the latest npm release (0.128.0 at the time of filing).

The important distinction here is that this is not only about a terminal's native Shift+Enter behavior. It is a common VS Code workaround that explicitly sends ESC + LF via workbench.action.terminal.sendSequence, and that sequence used to work with Codex CLI.