diff --git a/shells/ruby.nix b/shells/ruby.nix
index 8a98ab6..2174fc6 100644
--- a/shells/ruby.nix
+++ b/shells/ruby.nix
@@ -2,5 +2,6 @@
   buildInputs = with pkgs; [
     ruby_3_2
     postgresql_15
+    rubyPackages_3_2.rspec-core
   ];
 }