diff --git a/projectconf/sections/env/options/build/build_flags.rst b/projectconf/sections/env/options/build/build_flags.rst
index 4498b879a1..6d27eebcaa 100644
--- a/projectconf/sections/env/options/build/build_flags.rst
+++ b/projectconf/sections/env/options/build/build_flags.rst
@@ -181,7 +181,7 @@ for you:
 .. code:: ini
 
   [env:myenv]
-  extra_scripts = myscript.py
+  extra_scripts = pre:myscript.py
 
 **myscript.py**