diff --git a/config/tmux/tmux.conf b/config/tmux/tmux.conf
index aa70f93..048f1d4 100644
--- a/config/tmux/tmux.conf
+++ b/config/tmux/tmux.conf
@@ -16,6 +16,7 @@
 # -u : Unset the specified option.
 
 set -as terminal-features ",xterm-256color:RGB:clipboard:usstyle:strikethrough:overline"
+set -g allow-passthrough on             # Let apps query outer terminal (OSC 11 for fish theme detection)
 
 set -s escape-time 0                    # Address vim mode switching delay
 set -s set-clipboard on                 # System clipboard via OSC 52