If you're like me and have a default attach-session setup in your ~/.zshrc and but don't want VSCode to attach to it, then this is for you.

Just check if the name of parent process != 'code'

# check if parent is foot, then start 
tmux_run() {
  parent_process=$(ps -p $PPID -o comm=)
    if [[ "$parent_process" != "code" ]]; then
        if [ -z "$TMUX" ]; then
            tmux attach-session -t envy || tmux new -s envy
        fi
}
tmux_run

edit: switched to fish

function tmux_run
    set parent_process (ps -o comm= -p (ps -o ppid= -p $fish_pid | string trim))
    # Check if the parent process is not `code` or `zed-editor`
    if not test "$parent_process" = "code" -o "$parent_process" = "zed-editor"
        # Check if not already inside a tmux session
        if not set -q TMUX
            # Attach to tmux session "envy" or create it if it doesn't exist
            tmux attach-session -t envy || tmux new -s envy
        end
    end
end

save the function and add tmux_run to config.fish