diff --git a/tests/unit/test_d5b_perrow_lse.py b/tests/unit/test_d5b_perrow_lse.py
index 0765fff4..156cbcf8 100644
--- a/tests/unit/test_d5b_perrow_lse.py
+++ b/tests/unit/test_d5b_perrow_lse.py
@@ -161,6 +161,7 @@ def test_lse_kv_merge():
     ref_o, _ = reference_attention_with_lse(q[:, :, 0], k[:, :, 0], v, scale)
 
     # Kernel: two segments of 128, merge with per-row LSE + normalized O
+    # IMPORTANT: create kernel with s_k=128 (segment size), not s_k=256
     seg_size = 128
     o_norms = []
     lses = []