diff --git a/pkgs/tools/security/mitmproxy2swagger/default.nix b/pkgs/tools/security/mitmproxy2swagger/default.nix
index 2abcf2065ced..bf83c7303eef 100644
--- a/pkgs/tools/security/mitmproxy2swagger/default.nix
+++ b/pkgs/tools/security/mitmproxy2swagger/default.nix
@@ -17,6 +17,11 @@ python3.pkgs.buildPythonApplication rec {
 
   nativeBuildInputs = with python3.pkgs; [
     poetry-core
+    pythonRelaxDepsHook
+  ];
+
+  pythonRelaxDeps = [
+    "ruamel.yaml"
   ];
 
   propagatedBuildInputs = with python3.pkgs; [