[TMUX][ZSH] Label ssh panes with remote title or host alias

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tmux/.tmux.conf

@@ -43,6 +43,15 @@ bind - run-shell 'v="#{@venv}"; d="#{pane_current_path}"; if [ -n "$v" ]; then t
 # its global env carries one), regardless of what the source pane had.
 bind c new-window -e VIRTUAL_ENV=
 
+# ssh panes: the shell sets #{@ssh_host} and the pane title to the alias (see
+# zsh/lib/interactive.zsh); a remote that sets its own title overrides the
+# latter. Label ssh panes by title in the window name and, only in windows with
+# an ssh pane, in the pane border.
+set -g automatic-rename-format '#{?#{@ssh_host},#{=40:pane_title},#{?pane_in_mode,[tmux],#{pane_current_command}}#{?pane_dead,[dead],}}'
+set -g pane-border-format '#{?#{@ssh_host},#[bold] #{=60:pane_title} #[default],}'
+set-hook -g window-layout-changed \
+  'if -F "#{P:#{@ssh_host}}" "set -w pane-border-status top" "set -wu pane-border-status"'
+
 # Switch windows
 bind-key -n M-Left select-window -t -1
 bind-key -n M-Right select-window -t +1

zsh/lib/interactive.zsh

@@ -108,3 +108,53 @@ pastefinish() {
 zstyle :bracketed-paste-magic paste-init pasteinit
 zstyle :bracketed-paste-magic paste-finish pastefinish
 ZSH_AUTOSUGGEST_CLEAR_WIDGETS+=(bracketed-paste)
+
+# Mirror the ssh destination into a per-pane tmux option; .tmux.conf labels ssh
+# panes (window name, pane border only in windows with ssh panes) by title.
+_ssh_host_tmux() {
+    local -a set=(set -p -t $TMUX_PANE @ssh_host "$1")
+    [[ -n $1 ]] || set=(set -pu -t $TMUX_PANE @ssh_host)
+    tmux $set \; if -F -t $TMUX_PANE '#{P:#{@ssh_host}}' \
+        "set -w -t $TMUX_PANE pane-border-status top" \
+        "set -wu -t $TMUX_PANE pane-border-status" 2>/dev/null
+}
+_ssh_host_preexec() {
+    [[ -n $TMUX ]] || return
+    local -a w=(${(z)3})  # $2 is size-limited
+    while [[ $w[1] == *=* || $w[1] == (command|exec|noglob|nocorrect) ]]; do shift w; done
+    [[ ${w[1]:t} == ssh ]] || return
+    shift w
+    local host opt
+    while (( $#w )); do
+        case ${(Q)w[1]} in
+            --) host=${(Q)w[2]}; break ;;
+            -?*)
+                # option cluster; stop at the first flag that takes an argument
+                opt=${(Q)w[1]#-}; shift w
+                while [[ -n $opt ]]; do
+                    if [[ $opt[1] == [BbcDEeFIiJLlmOoPpRSWw] ]]; then
+                        [[ -n ${opt:1} ]] || shift w
+                        break
+                    fi
+                    opt=${opt:1}
+                done ;;
+            *) host=${(Q)w[1]}; break ;;
+        esac
+    done
+    [[ $host == ssh://* ]] && host=${${host#ssh://}%:<->}
+    host=${host##*@}
+    [[ -n $host ]] || return
+    _ssh_host_tmux $host
+    _ssh_host_set=1
+    # pane title starts as the alias; a remote that sets its own title wins.
+    # Runs after OMZ's preexec, so this replaces its "ssh ..." title.
+    print -rn -- $'\e]2;'"$host"$'\e\\'
+}
+_ssh_host_precmd() {
+    (( ${_ssh_host_set:-0} )) || return
+    _ssh_host_tmux ''
+    _ssh_host_set=0
+}
+autoload -Uz add-zsh-hook
+add-zsh-hook preexec _ssh_host_preexec
+add-zsh-hook precmd _ssh_host_precmd