diff --git a/OliveTin.proto b/OliveTin.proto
index 33bb7028..b93fd600 100644
--- a/OliveTin.proto
+++ b/OliveTin.proto
@@ -22,7 +22,7 @@ message StartActionResponse {
 	string stdout = 1;
 	string stderr = 2;
 	bool timedOut = 3;
-	int64 exitCode = 4;
+	int32 exitCode = 4;
 }
 
 service OliveTinApi {