diff --git a/manifest.dhall b/manifest.dhall
index ebc2b4b34b7750092786e7972b5d9af54cdb5b6d..1cef27afd4b66bd1d5a3218657e103eb537e80c7 100644
--- a/manifest.dhall
+++ b/manifest.dhall
@@ -276,6 +276,11 @@ in  [ callHackage "Cabal" "3.8.1.0"
         "https://github.com/haskell-effectful/kvstore-effectful"
         (Some "3502825423aea3a1af9384e9d751feea4599c60b")
         (Some "kvstore-effectful")
+    , callCabal2nix
+        "kvstore-effectful-spec"
+        "https://github.com/haskell-effectful/kvstore-effectful"
+        (Some "3502825423aea3a1af9384e9d751feea4599c60b")
+        (Some "kvstore-effectful-spec")
     , callHackage "lens" "5.2"
     , callHackage "lens-aeson" "1.2.1"
     , callHackage "lens-family-th" "0.5.2.1"
diff --git a/overlay.nix b/overlay.nix
index 45dec5e1fe47a7a3fecf85e5734a0978638b09f7..466d327e48acfa7cff13136b8165a5440e53a4e5 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -315,6 +315,8 @@ final: prev: with pkgs.haskell.lib; {
 
     kvstore-effectful = prev.callPackage (./pkgs/kvstore-effectful.nix) { };
 
+    kvstore-effectful-spec = prev.callPackage (./pkgs/kvstore-effectful-spec.nix) { };
+
     lens = prev.callPackage (./pkgs/lens.nix) { };
 
     lens-aeson = prev.callPackage (./pkgs/lens-aeson.nix) { };
diff --git a/pkgs/kvstore-effectful-spec.nix b/pkgs/kvstore-effectful-spec.nix
new file mode 100644
index 0000000000000000000000000000000000000000..c0536bc9bfb736e305954b5947888022b2404a83
--- /dev/null
+++ b/pkgs/kvstore-effectful-spec.nix
@@ -0,0 +1,24 @@
+{ mkDerivation, base, containers, effectful, effectful-core
+, fetchgit, hedgehog, kvstore-effectful, lib, tasty, tasty-hedgehog
+, transformers
+}:
+mkDerivation {
+  pname = "kvstore-effectful-spec";
+  version = "0.0.1.0";
+  src = fetchgit {
+    url = "https://github.com/haskell-effectful/kvstore-effectful";
+    sha256 = "1s78x8yqig17dhfwf2qbd01k8symzrjvg8w0i16mckyxpm28aqcq";
+    rev = "3502825423aea3a1af9384e9d751feea4599c60b";
+    fetchSubmodules = true;
+  };
+  postUnpack = "sourceRoot+=/kvstore-effectful-spec/; echo source root reset to $sourceRoot";
+  libraryHaskellDepends = [
+    base containers effectful effectful-core hedgehog kvstore-effectful
+    tasty tasty-hedgehog transformers
+  ];
+  doHaddock = false;
+  jailbreak = true;
+  doCheck = false;
+  hyperlinkSource = false;
+  license = lib.licenses.bsd3;
+}
\ No newline at end of file