diff --git a/src/Core/NBB.Core.Effects.FSharp/Effects.fs b/src/Core/NBB.Core.Effects.FSharp/Effects.fs
index 9a6e86ba..9c6b9b9e 100644
--- a/src/Core/NBB.Core.Effects.FSharp/Effects.fs
+++ b/src/Core/NBB.Core.Effects.FSharp/Effects.fs
@@ -41,6 +41,7 @@ module EffectBuilder =
         member _.ReturnFrom(value) = value
         member _.Combine(eff1, eff2) = Effect.bind (fun _ -> eff2) eff1
         member _.Zero() = Effect.pure' ()
+        member _.Delay(f) = f()
 
 
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