diff --git a/core/proto/README.md b/core/proto/README.md
new file mode 100644
index 0000000000000..d2b89a52e9274
--- /dev/null
+++ b/core/proto/README.md
@@ -0,0 +1,41 @@
+Conventions for the protos in this directory:
+
+1. As in the rest of Android, use 4 spaces to indent instead of 2.
+
+1. For protos based on Java files, use the same package as the Java file. For
+   example, `com.android.server.thing` instead of `com.android.server.thing.proto`.
+
+1. If the proto describes the top level output of dumpsys, it should contain
+   `Dump`. This makes it easy to understand that the proto is the dumpsys output
+   of a certain service, not the data structure of that service, e.g.
+   `WindowManagerServiceDumpProto` vs `WindowManagerServiceDumpProto`.
+
+   * Inner messages whose containing messages have the `Proto` suffix do not
+     need to have a `Proto` suffix. E.g:
+
+```
+message FooProto {
+    message Bar {
+        ...
+    }
+}
+```
+
+     vs
+
+```
+message FooProto {
+    message BarProto {
+        ...
+    }
+}
+```
+
+1. If the proto represents the structure of an object, it should have `Proto` as
+   its suffix. Please also include the full package path of the original object
+   as a comment to the proto message.
+
+1. Include units in the field names. For example, `screen_time_ms` vs
+   `screen_time`, or `file_size_bytes` or `file_size_mebibytes` vs `file_size`.
+
+1. Leave field numbers 50,000 - 100,000 reserved for OEMs.
diff --git a/core/proto/android/os/incident.proto b/core/proto/android/os/incident.proto
index bb9568bfcd8b1..4657dc478059c 100644
--- a/core/proto/android/os/incident.proto
+++ b/core/proto/android/os/incident.proto
@@ -280,4 +280,7 @@ message IncidentProto {
         (section).type = SECTION_DUMPSYS,
         (section).args = "usb --proto"
     ];
+
+    // Reserved for OEMs.
+    extensions 50000 to 100000;
 }