diff --git a/inline.go b/inline.go
index 5f563f8..cb3dc18 100644
--- a/inline.go
+++ b/inline.go
@@ -1,3 +1,5 @@
+// Code generated by tools/gen-jscore. DO NOT EDIT.
+
 package otto
 
 import (
diff --git a/token/token_const.go b/token/token_const.go
index a3e56f5..09ba017 100644
--- a/token/token_const.go
+++ b/token/token_const.go
@@ -1,3 +1,5 @@
+// Code generated by tools/gen-tokens. DO NOT EDIT.
+
 package token
 
 const (
diff --git a/tools/gen-jscore/templates/root.tmpl b/tools/gen-jscore/templates/root.tmpl
index 1951fbd..5878967 100644
--- a/tools/gen-jscore/templates/root.tmpl
+++ b/tools/gen-jscore/templates/root.tmpl
@@ -1,3 +1,5 @@
+// Code generated by tools/gen-jscore. DO NOT EDIT.
+
 package otto
 
 import (
diff --git a/tools/gen-tokens/templates/root.tmpl b/tools/gen-tokens/templates/root.tmpl
index 86e49fb..6b2d9cc 100644
--- a/tools/gen-tokens/templates/root.tmpl
+++ b/tools/gen-tokens/templates/root.tmpl
@@ -1,3 +1,5 @@
+// Code generated by tools/gen-tokens. DO NOT EDIT.
+
 package token
 
 const (