diff --git a/build/binary_tarball/spec/BUILD.bazel b/build/binary_tarball/spec/BUILD.bazel
new file mode 100644
index 0000000..bd02812
--- /dev/null
+++ b/build/binary_tarball/spec/BUILD.bazel
@@ -0,0 +1,36 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_proto_grpc_buf//:defs.bzl", "buf_proto_lint_test")
+
+buf_proto_lint_test(
+    name = "spec_proto_lint_test",
+    except_rules = [
+        "PACKAGE_VERSION_SUFFIX",
+    ],
+    protos = [":spec_proto"],
+    use_rules = [
+        "DEFAULT",
+        "COMMENTS",
+    ],
+)
+
+proto_library(
+    name = "spec_proto",
+    srcs = ["spec.proto"],
+    visibility = ["//visibility:public"],
+)
+
+go_proto_library(
+    name = "spec_go_proto",
+    importpath = "source.monogon.dev/build/binary_tarball/spec",
+    proto = ":spec_proto",
+    visibility = ["//visibility:public"],
+)
+
+go_library(
+    name = "spec",
+    embed = [":spec_go_proto"],
+    importpath = "source.monogon.dev/build/binary_tarball/spec",
+    visibility = ["//visibility:public"],
+)