diff --git a/src/core/Sidekick_core.ml b/src/core/Sidekick_core.ml
index 788d2b15..845ef121 100644
--- a/src/core/Sidekick_core.ml
+++ b/src/core/Sidekick_core.ml
@@ -538,6 +538,9 @@ module type SOLVER = sig
     val equal : t -> t -> bool
     val hash : t -> int
     val pp : t CCFormat.printer
+
+    val formula : t -> Lit.t
+    val sign : t -> bool
   end
 
   (** {3 Semantic values} *)