diff --git a/agent-cmd.sh b/agent-cmd.sh
index aded1e5..e40c5bd 100755
--- a/agent-cmd.sh
+++ b/agent-cmd.sh
@@ -13,11 +13,22 @@ if [ ${#agents[@]} -eq 0 ]; then
   exit 1
 fi
 
-# Minimize fzf prompt size while centering it.
+# This runs as the window's default-command, which tmux starts *before* the
+# popup client attaches. Until then the pane keeps a stale default size (often
+# 80x24), so wait for the attach before measuring — otherwise fzf is sized
+# against the wrong dimensions and renders far too small.
+for _ in $(seq 1 100); do
+  [ "$(tmux display-message -p '#{session_attached}')" -gt 0 ] && break
+  sleep 0.02
+done
+
+# Minimize fzf prompt size while centering it, using the real pane dimensions.
 width=24
 height=$((${#agents[@]} + 6))
-hmargin=$((($(tput cols) - width) / 2))
-vpad=$((($(tput lines) - height) / 2))
+cols=$(tmux display-message -p '#{pane_width}')
+lines=$(tmux display-message -p '#{pane_height}')
+hmargin=$(((cols - width) / 2))
+vpad=$(((lines - height) / 2))
 [ $hmargin -lt 0 ] && hmargin=0
 [ $vpad -lt 0 ] && vpad=0
 tput cup "$vpad" 0