Symptom

Since an unknown time when I press alt+right cannot move one word forward in VS Code integrated terminal.

Walked through the followings for a night...
https://code.visualstudio.com/docs/terminal/advanced#_send-a-custom-signal
https://github.com/microsoft/vscode/issues/251734
https://github.com/microsoft/vscode/issues/190629
It's not related to terminal.integrated.sendKeybindingsToShell in VS Code's settings.
Also not related to key conflict.

Adding the follow to VS Code's keyboard shortcut settings but in vain.

    {
        "key": "alt+left",
        "command": "workbench.action.terminal.sendSequence",
        "args": {
            "text": "\u001b[1;3D"
        },
        "when": "terminalFocus"
    },
    {
        "key": "alt+right",
        "command": "workbench.action.terminal.sendSequence",
        "args": {
            "text": "\u001b[1;3C"
        },
        "when": "terminalFocus"
    },

Reason

A hack hard codes alt+left behave like ctrl+left but didn't hack for alt+right as a pair...
Remove alt -> ctrl+arrow hack in favor of embedder-specific solutions
https://github.com/xtermjs/xterm.js/blob/41e8ae395937011d6bf6c7cb618b851791aed395/src/common/input/Keyboard.ts#L119
http://unix.stackexchange.com/a/108106

bindkey -e is missing in ~/.zshrc file which enable EMACS mode like alt+left alt+right ctrl+a ctrl+e etc. not working

Solution

Add bindkey -e in ~/.zshrc file.

Ref: How do I move the cursor to the beginning of the line in VSCode's terminal?

Specific commands like bindkey '^[[1;3C' forward-word and bindkey '^[[1;3D' backward-word won't work.