diff --git a/recipes/incoming-clib/gtk4-hello.toml b/recipes/incoming-clib/gtk4-hello.toml
new file mode 100644
index 00000000..017e29a5
--- /dev/null
+++ b/recipes/incoming-clib/gtk4-hello.toml
@@ -0,0 +1,47 @@
+# gtk4-hello — app GTK4 mínima de VALIDACIÓN: prueba que libgtk-4.a (static) es linkeable de verdad.
+# Reutiliza el tarball de GTK4 solo como acarreo de [source] (lo ignora); escribe su propio hello.c y
+# lo linkea ESTÁTICO contra todo el cierre GTK4 vía `pkg-config --static gtk4`. Si sella, el toolkit
+# de GUI del lab es usable por apps, no solo "compila". deps = cierre .pc completo + gtk4.
+name    = "gtk4-hello"
+version = "4.18.6"
+
+[source]
+tarball = "https://download.gnome.org/sources/gtk/4.18/gtk-4.18.6.tar.xz"
+sha256  = "e1817c650ddc3261f9a8345b3b22a26a5d80af154630dedc03cc7becefffd0fa"
+
+[build]
+compiler = "zig-cc"
+target   = "x86_64-linux-musl"
+link     = "static"
+
+[build.phases]
+# no-op: el tarball trae meson.build y el lab inyectaría `meson setup` por defecto si omito configure.
+configure = "true"
+compile = '''
+cat > hammer_hello.c <<'CEOF'
+#include <gtk/gtk.h>
+static void activate(GtkApplication *app, gpointer user_data) {
+  GtkWidget *win = gtk_application_window_new(app);
+  gtk_window_set_title(GTK_WINDOW(win), "Hola desde hammer");
+  gtk_window_set_default_size(GTK_WINDOW(win), 360, 220);
+  GtkWidget *label = gtk_label_new("GTK4 static-musl ✓ (zig cc)");
+  gtk_window_set_child(GTK_WINDOW(win), label);
+  gtk_window_present(GTK_WINDOW(win));
+}
+int main(int argc, char **argv) {
+  GtkApplication *app = gtk_application_new("org.hammer.hola", G_APPLICATION_DEFAULT_FLAGS);
+  g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
+  int status = g_application_run(G_APPLICATION(app), argc, argv);
+  g_object_unref(app);
+  return status;
+}
+CEOF
+# gtk4.pc NO declara Libs.private (asume link dinámico contra libgtk-4.so); para ESTÁTICO hay que sumar
+# las privadas que gdk/gsk linkean directo (harfbuzz-subset, epoxy, wayland, xkbcommon, tiff, jpeg).
+export PKG_CONFIG_PATH=/usr/lib/pkgconfig
+zig cc -mcpu=baseline -static hammer_hello.c -o gtk4-hello $(pkg-config --cflags --libs --static gtk4 harfbuzz-subset epoxy xkbcommon wayland-client wayland-egl libtiff-4 libjpeg cairo-script-interpreter)
+'''
+install = "mkdir -p /out/usr/bin && cp gtk4-hello /out/usr/bin/gtk4-hello"
+
+[deps]
+build = ["pkgconf", "gtk4", "pango", "gdk-pixbuf", "cairo", "graphene", "glib", "harfbuzz", "fribidi", "fontconfig", "freetype", "pixman", "libpng", "expat", "libjpeg-turbo", "libtiff", "libepoxy", "wayland", "libxkbcommon", "libdrm", "pcre2", "libffi", "zlib", "mesa"]
diff --git a/recipes/incoming-clib/gtk4.toml b/recipes/incoming-clib/gtk4.toml
index 5d2349c6..e4b78d85 100644
--- a/recipes/incoming-clib/gtk4.toml
+++ b/recipes/incoming-clib/gtk4.toml
@@ -20,9 +20,20 @@ link     = "static"
 # "libgtk_dep" NO es substring de "libgtk_static_dep" ⇒ no toca las que ya usan el estático.
 configure = "sed -i 's/libgtk_dep/libgtk_static_dep/g' tools/meson.build && PKG_CONFIG_PATH=/usr/lib/pkgconfig PYTHONPATH=/usr/lib/python3.12/site-packages meson setup output --prefix=/usr --buildtype=release --wrap-mode=nodownload --prefer-static -Ddefault_library=static -Dwayland-backend=true -Dx11-backend=false -Dbroadway-backend=false -Dwin32-backend=false -Dmacos-backend=false -Dvulkan=disabled -Dintrospection=disabled -Dbuild-demos=false -Dbuild-testsuite=false -Dbuild-tests=false -Dbuild-examples=false -Dmedia-gstreamer=disabled -Dprint-cups=disabled -Dprint-cpdb=disabled -Dcloudproviders=disabled -Dsysprof=disabled -Dtracker=disabled -Dcolord=disabled -Df16c=disabled -Ddocumentation=false -Dman-pages=false -Dc_args=-Wno-error=date-time"
 compile   = "PYTHONPATH=/usr/lib/python3.12/site-packages ninja -C output"
-# meson instala solo libgtk-4.so; copio el static_library('gtk') (libgtk.a, GTK completo) como libgtk-4.a
-# para que `-lgtk-4` + `-static` resuelva al estático (el lab es static-musl).
-install   = "PYTHONPATH=/usr/lib/python3.12/site-packages DESTDIR=/out meson install -C output --no-rebuild && cp output/gtk/libgtk.a /out/usr/lib/libgtk-4.a"
+# meson instala solo libgtk-4.so y genera convenience-libs THIN (gtk/gdk/gsk por separado, referencian
+# los .o por ruta → inútiles fuera del build dir). Fusiono los tres en UN archive GORDO libgtk-4.a (embebe
+# todos los .o) para que `-lgtk-4` + `-static` linkee de verdad en el lab static-musl.
+install = '''
+PYTHONPATH=/usr/lib/python3.12/site-packages DESTDIR=/out meson install -C output --no-rebuild
+rm -f /out/usr/lib/libgtk-4.a
+cd output
+objs=""
+for a in $(find . -name '*.a'); do
+  d=$(dirname "$a"); b=$(basename "$a")
+  for o in $(cd "$d" && zig ar t "$b"); do objs="$objs $d/$o"; done
+done
+zig ar rcs /out/usr/lib/libgtk-4.a $objs
+'''
 
 [deps]
 build = ["meson", "samurai", "python3", "pkgconf", "glib", "cairo", "pango", "gdk-pixbuf", "graphene", "libepoxy", "wayland", "wayland-protocols", "libxkbcommon", "libdrm", "fontconfig", "harfbuzz", "fribidi", "libpng", "pixman", "freetype", "expat", "libffi", "pcre2", "zlib", "libjpeg-turbo", "libtiff", "mesa"]