diff --git a/ci/requirements.txt b/ci/requirements.txt
index ff785a6..74d020f 100644
--- a/ci/requirements.txt
+++ b/ci/requirements.txt
@@ -2,3 +2,4 @@ harmony-py
 xq
 jupyterlab-quarto
 jupyter-desktop-server==0.1.3
+graphviz