diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b6cbfaa..8daa5eb 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,3 +1,17 @@
+# Copyright 2023 Mozilla Foundation
+#
+#  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.
+
 name: Test sccache
 
 on: [push, pull_request]
diff --git a/dist/index.js b/dist/index.js
index d0279bd..d14a40c 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -6,6 +6,19 @@
 
 "use strict";
 
+// Copyright 2023 Mozilla Foundation
+//
+// 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.
 var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
     if (k2 === undefined) k2 = k;
     var desc = Object.getOwnPropertyDescriptor(m, k);
@@ -83,7 +96,7 @@ function getArch() {
         case 'arm64':
             return 'aarch64';
         default:
-            return Error('not supported arch');
+            return Error('Unsupported arch "${process.arch}"');
     }
 }
 function getPlatform() {
@@ -95,7 +108,7 @@ function getPlatform() {
         case 'linux':
             return 'unknown-linux-musl';
         default:
-            return Error('not supported platform');
+            return Error('Unsupported platform "${process.platform}"');
     }
 }
 function getExtension() {
diff --git a/src/sccache.ts b/src/sccache.ts
index 6caf64e..30264bd 100644
--- a/src/sccache.ts
+++ b/src/sccache.ts
@@ -1,3 +1,17 @@
+// Copyright 2023 Mozilla Foundation
+//
+// 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.
+
 import * as core from '@actions/core';
 import {
   downloadTool,
@@ -58,7 +72,7 @@ function getArch(): Error | string {
     case 'arm64':
       return 'aarch64';
     default:
-      return Error('not supported arch');
+      return Error('Unsupported arch "${process.arch}"');
   }
 }
 
@@ -71,7 +85,7 @@ function getPlatform(): Error | string {
     case 'linux':
       return 'unknown-linux-musl';
     default:
-      return Error('not supported platform');
+      return Error('Unsupported platform "${process.platform}"');
   }
 }