diff --git a/.github/workflows/workspace-validation.yml b/.github/workflows/workspace-validation.yml
index d6898ef..4be04d3 100644
--- a/.github/workflows/workspace-validation.yml
+++ b/.github/workflows/workspace-validation.yml
@@ -117,6 +117,11 @@ jobs:
           # below shadow the PyAuto packages via PYTHONPATH.
           pip install "autolens[optional]"
           pip install "jax>=0.7,<0.11" "jaxlib>=0.7,<0.11"
+          # nufftax backs the interferometer TransformerNUFFT and is NOT pulled
+          # transitively by autolens[optional]; without it every interferometer
+          # simulator (and its downstream scripts) fails fast. Matches the pin
+          # PyAutoArray declares (jax 0.10.x + nufftax 0.4.x is the tested combo).
+          pip install "nufftax>=0.4.0,<0.5.0"
       - name: Run Python scripts
         run: |
           LIBS="$(pwd)/libs"