diff --git a/contrib/xos/xosoptions.proto b/contrib/xos/xosoptions.proto
new file mode 100644
index 0000000..0494ada
--- /dev/null
+++ b/contrib/xos/xosoptions.proto
@@ -0,0 +1,36 @@
+syntax = "proto3";
+
+package xos;
+
+import "google/protobuf/descriptor.proto";
+
+message ValRule {
+  int32 maxLength = 1;
+  bool nonNull = 2;
+  bool unique = 3;
+}
+
+message ForeignKeyRule {
+  string modelName = 1;
+  string reverseFieldName = 2;
+}
+
+message ReverseForeignKeyRule {
+  string modelName = 1;
+}
+
+message ManyToManyForeignKeyRule {
+  string modelName = 1;
+}
+
+extend google.protobuf.FieldOptions {
+  ValRule val = 1001;
+  ForeignKeyRule foreignKey = 1002;
+  ReverseForeignKeyRule reverseForeignKey = 1003;
+  ManyToManyForeignKeyRule manyToManyForeignKey = 1004;
+}
+
+extend google.protobuf.MessageOptions {
+  string contentTypeId = 1001;
+}
+