diff --git a/nix/packages.nix b/nix/packages.nix
index 79de8fac89..6202168733 100644
--- a/nix/packages.nix
+++ b/nix/packages.nix
@@ -22,6 +22,7 @@ in
     git-lfs
     gnumake
     gnupg # needed for signing commits & codecov/codecov-action
+    graphviz
     llvmPackages_22.clang-tools
     less # needed for git diff
     mold