diff --git a/Project.toml b/Project.toml
index c845f6c..7dd6f30 100644
--- a/Project.toml
+++ b/Project.toml
@@ -26,6 +26,7 @@ InteractiveErrorsJuliaFormatterExt = "JuliaFormatter"
 InteractiveErrorsOhMyREPLExt = "OhMyREPL"
 
 [compat]
+Cthulhu = "2"
 FoldingTrees = "1.1"
 IterTools = "1"
 PackageExtensionCompat = "1"