diff --git a/util/design/mubi/BUILD b/util/design/mubi/BUILD
new file mode 100644
index 0000000..ff79c57
--- /dev/null
+++ b/util/design/mubi/BUILD
@@ -0,0 +1,14 @@
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+load("@rules_python//python:defs.bzl", "py_library")
+load("@ot_python_deps//:requirements.bzl", "requirement")
+
+package(default_visibility = ["//visibility:public"])
+
+py_library(
+    name = "prim_mubi",
+    srcs = ["prim_mubi.py"],
+    deps = [requirement("mako")],
+)