diff --git a/pkgs/development/ocaml-modules/atd/default.nix b/pkgs/development/ocaml-modules/atd/default.nix
index ae0bbf36b21..61dd0f1084c 100644
--- a/pkgs/development/ocaml-modules/atd/default.nix
+++ b/pkgs/development/ocaml-modules/atd/default.nix
@@ -1,4 +1,4 @@
-{ lib, atdgen-codec-runtime, menhir, easy-format, buildDunePackage, which, re, nixosTests }:
+{ lib, atdgen-codec-runtime, menhir, easy-format, buildDunePackage, re, yojson, nixosTests }:
 
 buildDunePackage rec {
   pname = "atd";
@@ -6,9 +6,8 @@ buildDunePackage rec {
 
   minimalOCamlVersion = "4.08";
 
-  nativeBuildInputs = [ which menhir ];
-  buildInputs = [ re ];
-  propagatedBuildInputs = [ easy-format ];
+  nativeBuildInputs = [ menhir ];
+  propagatedBuildInputs = [ easy-format re yojson ];
 
   strictDeps = true;
 
diff --git a/pkgs/development/ocaml-modules/atdgen/codec-runtime.nix b/pkgs/development/ocaml-modules/atdgen/codec-runtime.nix
index 9ad64549ea3..a2f3b32b7fc 100644
--- a/pkgs/development/ocaml-modules/atdgen/codec-runtime.nix
+++ b/pkgs/development/ocaml-modules/atdgen/codec-runtime.nix
@@ -2,11 +2,11 @@
 
 buildDunePackage rec {
   pname = "atdgen-codec-runtime";
-  version = "2.4.1";
+  version = "2.9.1";
 
   src = fetchurl {
-    url = "https://github.com/ahrefs/atd/releases/download/${version}/atdgen-codec-runtime-${version}.tbz";
-    sha256 = "sha256:16888rnvhgh5yxxsnzsj10g5pzs1l4dn27n23kk2f4641dn26s3a";
+    url = "https://github.com/ahrefs/atd/releases/download/${version}/atdts-${version}.tbz";
+    sha256 = "sha256-OdwaUR0Ix0Oz8NDm36nIyvIRzF+r/pKgiej1fhcOmuQ=";
   };
 
   meta = {
diff --git a/pkgs/development/ocaml-modules/atdgen/default.nix b/pkgs/development/ocaml-modules/atdgen/default.nix
index 807276d31b2..0658130f9e0 100644
--- a/pkgs/development/ocaml-modules/atdgen/default.nix
+++ b/pkgs/development/ocaml-modules/atdgen/default.nix
@@ -1,4 +1,6 @@
-{ buildDunePackage, alcotest, atd, atdgen-codec-runtime, atdgen-runtime, biniou, re, yojson }:
+{ buildDunePackage, alcotest, atd, atdgen-codec-runtime, atdgen-runtime, biniou, re, yojson
+, python3
+}:
 
 buildDunePackage {
   pname = "atdgen";
@@ -9,7 +11,9 @@ buildDunePackage {
   propagatedBuildInputs = [ atdgen-runtime ];
 
   doCheck = true;
-  checkInputs = [ alcotest atdgen-codec-runtime ];
+  checkInputs = [ alcotest atdgen-codec-runtime
+    (python3.withPackages (ps: [ ps.jsonschema ]))
+  ];
 
   meta = (builtins.removeAttrs atd.meta [ "mainProgram" ]) // {
     description = "Generates efficient JSON serializers, deserializers and validators";