diff --git a/.github/workflows/gen.go b/.github/workflows/gen.go
index d4d12be..43f2fb0 100644
--- a/.github/workflows/gen.go
+++ b/.github/workflows/gen.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The CUE Authors
+//
+// 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.
+
 package workflows
 
 //go:generate go run cuelang.org/go/cmd/cue cmd genworkflows cuelang.org/go/internal/ci
diff --git a/cmd/cue/cmd/script_test.go b/cmd/cue/cmd/script_test.go
index 0c341e1..71671be 100644
--- a/cmd/cue/cmd/script_test.go
+++ b/cmd/cue/cmd/script_test.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The CUE Authors
+//
+// 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.
+
 package cmd
 
 import (
diff --git a/gen.go b/gen.go
index cf14afe..042ebc8 100644
--- a/gen.go
+++ b/gen.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The CUE Authors
+//
+// 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.
+
 package cue
 
 //go:generate go generate ./.github/workflows
diff --git a/tools.go b/tools.go
index 0a8cefc..0a270cf 100644
--- a/tools.go
+++ b/tools.go
@@ -1,3 +1,17 @@
+// Copyright 2020 The CUE Authors
+//
+// 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.
+
 // +build tools
 
 package tools