diff --git a/test_autofit/non_linear/search/mcmc/test_blackjax_nuts.py b/test_autofit/non_linear/search/mcmc/test_blackjax_nuts.py
index 1621a73a1..fbc55bd28 100644
--- a/test_autofit/non_linear/search/mcmc/test_blackjax_nuts.py
+++ b/test_autofit/non_linear/search/mcmc/test_blackjax_nuts.py
@@ -8,12 +8,12 @@
     _times_from_positions,
 )
 
-# `_times_from_positions` is jax-backed; it needs jax installed to run (jax
-# ships via the `[optional]` extras). The NumPy-only Python-version matrix has
-# no jax, so skip there rather than fail.
-requires_jax = pytest.mark.skipif(
-    importlib.util.find_spec("jax") is None,
-    reason="requires jax (installed via the [optional] extras; absent on the NumPy-only matrix env)",
+# `_times_from_positions` runs blackjax (which pulls jax); both ship via the
+# `[optional]` extras. The Python-version matrix installs autofit without those
+# extras, so skip there rather than fail with `No module named 'blackjax'`.
+requires_blackjax = pytest.mark.skipif(
+    importlib.util.find_spec("blackjax") is None,
+    reason="requires blackjax (installed via the [optional] extras; absent on the matrix env)",
 )
 
 pytestmark = pytest.mark.filterwarnings("ignore::FutureWarning")
@@ -101,7 +101,7 @@ def test__identifier_fields_distinguish_run_shape():
     assert (c.num_warmup, c.num_samples, c.num_chains) == (100, 999, 1)
 
 
-@requires_jax
+@requires_blackjax
 def test__times_from_positions_clamps_low_ess():
     # Construct a degenerate "chain" — every sample is identical → ESS
     # collapses; the clamp must keep ``times`` finite and equal to N.
@@ -118,7 +118,7 @@ def test__times_from_positions_clamps_low_ess():
     assert np.all(times <= n_samples + 1e-9)
 
 
-@requires_jax
+@requires_blackjax
 def test__times_from_positions_independent_chain():
     # Independent draws → ESS ≈ N, so τ ≈ 1.
     rng = np.random.default_rng(1)