diff --git a/flake.nix b/flake.nix
index 10916bd..8af195c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -36,6 +36,8 @@
         buildInputs = with pkgs; [
           gnumake
           pandoc
+          pandoc-plantuml-filter
+          plantuml
           (texlive.combine {
             inherit (texlive)
               scheme-small