diff --git a/tools/aconfig/src/protos.rs b/tools/aconfig/src/protos.rs
new file mode 100644
index 0000000..99d584a
--- /dev/null
+++ b/tools/aconfig/src/protos.rs
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// When building with the Android tool-chain
+//
+//   - an external crate `aconfig_protos` will be generated
+//   - the feature "cargo" will be disabled
+//
+// When building with cargo
+//
+//   - a local sub-module will be generated in OUT_DIR and included in this file
+//   - the feature "cargo" will be enabled
+//
+// This module hides these differences from the rest of aconfig.
+
+// When building with the Android tool-chain:
+#[cfg(not(feature = "cargo"))]
+pub use aconfig_protos::aconfig::Placeholder;
+
+// When building with cargo:
+#[cfg(feature = "cargo")]
+include!(concat!(env!("OUT_DIR"), "/aconfig_proto/mod.rs"));
+
+#[cfg(feature = "cargo")]
+pub use aconfig::Placeholder;