diff --git a/tag-zsh/zsh/configs/tmux.zsh b/tag-zsh/zsh/configs/tmux.zsh
new file mode 100644
index 0000000..98a4386
--- /dev/null
+++ b/tag-zsh/zsh/configs/tmux.zsh
@@ -0,0 +1,9 @@
+_not_inside_tmux() {
+  [[ -z "$TMUX" ]]
+}
+
+ensure_tmux_is_running() {
+  if _not_inside_tmux; then
+    tat
+  fi
+}
diff --git a/tag-zsh/zshrc b/tag-zsh/zshrc
index c8273fe..a5185b3 100644
--- a/tag-zsh/zshrc
+++ b/tag-zsh/zshrc
@@ -15,5 +15,7 @@ for function in $HOME/.zsh/functions/*; do
   source $function
 done
 
+ensure_tmux_is_running
+
 # Local config
 [[ -f ~/.zshrc.local ]] && source ~/.zshrc.local