diff --git a/src/backend/modern.lisp b/src/backend/modern.lisp
index cd633f2..fa9fe2c 100644
--- a/src/backend/modern.lisp
+++ b/src/backend/modern.lisp
@@ -163,13 +163,12 @@ as a fallback when a keyword is not in *named-colors*.")
 
 (defmethod backend-size ((b modern-backend))
   (or       ;; stty size via subprocess — most reliable across all systems.
-      ;; Returns "ROWS COLS". Uses :input :interactive so the subprocess
-      ;; opens /dev/tty for its stdin (SBCL's stdin is the load file).
+      ;; Returns "ROWS COLS". stty size queries the terminal via ioctl,
+      ;; not stdin, so no :input redirection is needed.
       (multiple-value-bind (cols rows)
           (ignore-errors
             (let* ((out (uiop:run-program '("stty" "size")
                                           :output :string
-                                          :input :interactive
                                           :ignore-error-status t))
                    (parts (and out (uiop:split-string
                                      (string-trim '(#\newline #\space) out)))))
diff --git a/src/backend/simple.lisp b/src/backend/simple.lisp
index d0a64a6..7ce8a55 100644
--- a/src/backend/simple.lisp
+++ b/src/backend/simple.lisp
@@ -27,7 +27,6 @@
           (ignore-errors
             (let* ((out (uiop:run-program '("stty" "size")
                                           :output :string
-                                          :input :interactive
                                           :ignore-error-status t))
                    (parts (and out (uiop:split-string
                                      (string-trim '(#\newline #\space) out)))))