diff --git a/grpc_core/lib/grpc/rpc_error.ex b/grpc_core/lib/grpc/rpc_error.ex
index f0766e7a..9f0a16e4 100644
--- a/grpc_core/lib/grpc/rpc_error.ex
+++ b/grpc_core/lib/grpc/rpc_error.ex
@@ -58,7 +58,7 @@ defmodule GRPC.RPCError do
   @type t :: %__MODULE__{
           status: GRPC.Status.t(),
           message: String.t(),
-          details: [Google.Protobuf.Any.t()]
+          details: [Google.Protobuf.Any.t()] | nil
         }
 
   alias GRPC.Status