diff --git a/stack.yaml b/stack.yaml
index b6aeee5..4f6a40d 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -22,7 +22,9 @@ extra-deps:
   - unordered-containers-0.2.6.0
 
 # Override default flag values for local packages and extra-deps
-flags: {}
+flags:
+  vervis:
+    dev: true
 
 # Extra package databases containing global packages
 extra-package-dbs: []