diff --git a/proxy.proto b/proxy.proto
new file mode 100644
index 0000000..d35a2c3
--- /dev/null
+++ b/proxy.proto
@@ -0,0 +1,15 @@
+syntax = "proto3";
+package proto;
+
+message RunCommandRequest {
+    string command = 1;
+};
+
+message RunCommandResponse {
+    string effective_command = 1;
+    repeated string lines = 2;
+};
+
+service M6220Proxy {
+    rpc RunCommand(RunCommandRequest) returns (RunCommandResponse);
+};