diff --git a/proto/optional_output_wrapper.rs b/proto/optional_output_wrapper.rs
new file mode 100644
index 0000000..59eba1b
--- /dev/null
+++ b/proto/optional_output_wrapper.rs
@@ -0,0 +1,57 @@
+// Copyright 2020 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::env::args;
+use std::error;
+use std::fs::File;
+use std::path::Path;
+use std::process::Command;
+
+// A simple wrapper around a binary to ensure we always create some outputs
+// Optional outputs are not available in Skylark :(
+// Syntax: $0 output1 output2 ... -- program  [arg1...argn]
+fn ensure() -> Result<i32, Box<dyn error::Error>> {
+    let index = args().position(|a| a == "--").ok_or("no --")?;
+    let optional_outputs = args().take(index).collect::<Vec<String>>();
+    let exe = args().nth(index + 1).ok_or("no exe")?;
+    let exe_args = args().skip(index + 2).collect::<Vec<String>>();
+    if exe_args.is_empty() {
+        return Err("no exe args".into());
+    }
+    match Command::new(exe).args(exe_args).status()?.code() {
+        Some(code) => {
+            if code == 0 {
+                for out in optional_outputs {
+                    if !Path::new(&out).exists() {
+                        let _ = File::create(out)?;
+                    }
+                }
+            }
+            Ok(code)
+        }
+        None => Err("process killed".into()),
+    }
+}
+
+fn main() {
+    std::process::exit(match ensure() {
+        Ok(exit_code) => exit_code,
+        Err(e) => {
+            println!("Usage: [optional_output1...optional_outputN] -- program [arg1...argn]");
+            println!("{:?}", args());
+            println!("{:?}", e);
+            -1
+        }
+    });
+}