diff --git a/build/toolbase/BUILD.bazel b/build/toolbase/BUILD.bazel
new file mode 100644
index 0000000..6fd1489
--- /dev/null
+++ b/build/toolbase/BUILD.bazel
@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "doc.go",
+        "label.go",
+        "workspace.go",
+    ],
+    importpath = "source.monogon.dev/build/toolbase",
+    visibility = ["//visibility:public"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["label_test.go"],
+    embed = [":go_default_library"],
+    deps = ["@com_github_google_go_cmp//cmp:go_default_library"],
+)