diff --git a/proto/caosdb/acm/v1alpha1/main.proto b/proto/caosdb/acm/v1alpha1/main.proto
index 610817cce223e2a6da41a77b33dbb58e1c93e3fa..a84148fdc89b40df098d3698be2d79a5012867b1 100644
--- a/proto/caosdb/acm/v1alpha1/main.proto
+++ b/proto/caosdb/acm/v1alpha1/main.proto
@@ -82,8 +82,10 @@ message CreateSingleRoleRequest {
   // The new role.
   Role role = 1;
 }
+
 // Response message for the CreateSingleRole RPC
 message CreateSingleRoleResponse {}
+
 // Request message for the <+TODO+> RPC
 message RetrieveSingleRoleRequest {}
 // Response message for the <+TODO+> RPC
@@ -101,11 +103,21 @@ message DeleteSingleRoleResponse {}
 // USER STUFF
 ///////////////////////////////////////////
 
+// UserStatus
+enum UserStatus {
+  // The user status is unspecified/unknown.
+  USER_STATUS_UNSPECIFIED = 0;
+  // The user is inactive and cannot sign in.
+  USER_STATUS_INACTIVE = 1;
+  // The user is active and can sign in.
+  USER_STATUS_ACTIVE = 2;
+}
+
 // User
 message User {
   // Indicates whether the user is active. Only active users can sign in and
   // interact with the CaosDB Server.
-  string active = 1;
+  UserStatus status = 1;
   // Realm of this user. The realm is the authority which can authenticate this
   // user, e.g. 'PAM' when the user is a (POSIX) user from the server's host, or
   // 'CaosDB' when CaosDB Server itself can authenticate the user.
@@ -135,10 +147,17 @@ message ListUsersResponse {
   repeated User users = 2;
 }
 
-// Request message for the <+TODO+> RPC
-message CreateSingleUserRequest {}
-// Response message for the <+TODO+> RPC
+// Request message for the CreateSingleUser RPC
+message CreateSingleUserRequest {
+  // The new user.
+  User user = 1;
+  // The new password.
+  string password = 2;
+}
+
+// Response message for the CreateSingeUser RPC
 message CreateSingleUserResponse {}
+
 // Request message for the <+TODO+> RPC
 message RetrieveSingleUserRequest {}
 // Response message for the <+TODO+> RPC