diff --git a/src/backend/wayland/wl_backend.c b/src/backend/wayland/wl_backend.c
index ea0fd3b..000de03 100644
--- a/src/backend/wayland/wl_backend.c
+++ b/src/backend/wayland/wl_backend.c
@@ -21,6 +21,8 @@
  * Phase 41: prop_get_wm_class and window_fetch_name return XDG app_id/title.
  * Phase 42: window_get_client_attrs returns WCLIENT_VIEWABLE + surface
  * geometry for mapped XDG toplevels.
+ * Phase 43: focus_set delivers keyboard focus via wlr_seat; headless keyboard
+ * device created and attached to seat; mapped toplevels auto-focused.
  */
 
 #ifdef HAVE_CONFIG_H
@@ -42,6 +44,7 @@
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_seat.h>
+#include <wlr/types/wlr_keyboard.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/box.h>
 /* Generated xdg-shell protocol implementation (Wayland glue code) */
@@ -107,6 +110,8 @@ struct wl_compositor_state {
     struct wl_list                  toplevel_list;             /* wl_toplevel_view.link */
     struct wl_list                  ctx_lists[3];              /* one per WContextKey */
     unsigned long                   next_synthetic_id;         /* >= 0x10000000 */
+    /* Phase 43: headless keyboard device for seat keyboard focus */
+    struct wlr_input_device        *keyboard_dev;
     char                            socket_name[64];  /* Phase 34: e.g. "wayland-0" */
     int                             started; /* non-zero after successful display_open */
 };
@@ -135,6 +140,9 @@ frame_timer_cb(void *data)
 #define VIEW_FROM_LISTENER(ptr, field) \
     ((struct wl_toplevel_view *)((char *)(ptr) - offsetof(struct wl_toplevel_view, field)))
 
+/* Phase 43: forward declaration — defined in the focus section below. */
+static void wl_focus_set(WNativeWindow win, int revert_to, unsigned long timestamp);
+
 /* Phase 41: look up the view for a given synthetic WNativeWindow ID. */
 static struct wl_toplevel_view *
 wl_find_view_by_id(WNativeWindow id)
@@ -166,13 +174,16 @@ handle_toplevel_map(struct wl_listener *listener, void *data)
         WScreen *scr = wScreenWithNumber(0);
         if (scr) {
             WWindow *wwin = wManageWindow(scr, view->id);
-            if (wwin)
+            if (wwin) {
                 wwarning("wl_backend: wManageWindow succeeded id=0x%lx "
                          "class=%s name=%s geo=%dx%d",
                          view->id,
                          wwin->wm_class    ? wwin->wm_class    : "(none)",
                          wwin->wm_instance ? wwin->wm_instance : "(none)",
                          wwin->client.width, wwin->client.height);
+                /* Phase 43: focus the newly mapped toplevel. */
+                wl_focus_set(view->id, 0, 0);
+            }
         }
     }
 }
@@ -342,6 +353,15 @@ wl_display_open(const char *name)
     if (wl_state.output)
         wlr_output_create_global(wl_state.output);
 
+    /* Phase 43: create a headless keyboard and attach it to the seat so
+     * wlr_seat_keyboard_notify_enter() can deliver keyboard focus. */
+    wl_state.keyboard_dev =
+        wlr_headless_add_input_device(wl_state.backend, WLR_INPUT_DEVICE_KEYBOARD);
+    if (wl_state.keyboard_dev) {
+        wlr_seat_set_keyboard(wl_state.seat, wl_state.keyboard_dev);
+        wlr_seat_set_capabilities(wl_state.seat, WL_SEAT_CAPABILITY_KEYBOARD);
+    }
+
     /* Phase 38: initialise per-toplevel tracking and context store. */
     wl_list_init(&wl_state.toplevel_list);
     {
@@ -533,7 +553,19 @@ wl_context_delete(WNativeWindow win, WContextKey key)
 
 static void
 wl_focus_set(WNativeWindow win, int revert_to, unsigned long timestamp)
-{ (void)win; (void)revert_to; (void)timestamp; }
+{
+    /* Phase 43: deliver keyboard focus to the XDG toplevel surface. */
+    (void)revert_to; (void)timestamp;
+    if (!wl_state.seat || !wl_state.keyboard_dev)
+        return;
+    struct wl_toplevel_view *v = wl_find_view_by_id(win);
+    if (!v || !v->xdg_surface || !v->xdg_surface->surface)
+        return;
+    wlr_seat_keyboard_notify_enter(wl_state.seat,
+                                   v->xdg_surface->surface,
+                                   NULL, 0, NULL);
+    wwarning("wl_backend: focus_set id=0x%lx", win);
+}
 
 /* ------------------------------------------------------------------ */
 /* Key / button grabs                                                  */
diff --git a/tests/wl-smoke-test.sh b/tests/wl-smoke-test.sh
index 3faa3ce..d6ee4be 100755
--- a/tests/wl-smoke-test.sh
+++ b/tests/wl-smoke-test.sh
@@ -26,6 +26,8 @@
 #      succeeded" log includes class=org.freedesktop.weston.simple-shm
 #  12. (Phase 42) window_get_client_attrs returns WCLIENT_VIEWABLE + geometry:
 #      "wManageWindow succeeded" log includes geo= with non-zero size
+#  13. (Phase 43) focus_set delivers keyboard focus via wlr_seat: compositor
+#      logs "focus_set id=" after wManageWindow succeeds
 #
 # This test grows as wl_backend vtable slots are implemented.
 #
@@ -177,6 +179,11 @@ if command -v weston-simple-shm >/dev/null 2>&1; then
     GEO=$(grep -o 'geo=[0-9]*x[0-9]*' /tmp/wl-smoke-stderr | head -1)
     [ -n "$GEO" ] || die "wManageWindow did not log geo= geometry"
     echo "  geometry check: client geometry logged as $GEO"
+
+    # -- 13. Phase 43: keyboard focus delivered to toplevel --------------
+    grep -q 'focus_set id=' /tmp/wl-smoke-stderr \
+        || die "compositor did not log focus_set (keyboard focus not delivered)"
+    echo "  focus check: keyboard focus delivered to mapped toplevel"
 else
     echo "  client check: skipped (weston-simple-shm not installed)"
 fi