diff --git a/src/coolrl_lost_cities/games/classic/deep_cfr/encoding.pyx b/src/coolrl_lost_cities/games/classic/deep_cfr/encoding.pyx
index 6fcd454..062a567 100644
--- a/src/coolrl_lost_cities/games/classic/deep_cfr/encoding.pyx
+++ b/src/coolrl_lost_cities/games/classic/deep_cfr/encoding.pyx
@@ -236,6 +236,8 @@ cdef int _append_slot_aware_playability_features_c(GameState state, int player,
 
     for slot in range(state.hand_size):
         if slot >= state.hand_lens[player]:
+            for color in range(SLOT_AWARE_PLAYABILITY_PER_SLOT):
+                out[idx + color] = 0.0
             idx += SLOT_AWARE_PLAYABILITY_PER_SLOT
             continue
         card = state.hand_cards[state._hand_index(player, slot)]
diff --git a/tests/games/classic/test_deep_cfr_trainer.py b/tests/games/classic/test_deep_cfr_trainer.py
index 97cd192..241d57d 100644
--- a/tests/games/classic/test_deep_cfr_trainer.py
+++ b/tests/games/classic/test_deep_cfr_trainer.py
@@ -165,6 +165,20 @@ def test_deep_cfr_playability_encoding_extends_input_shape() -> None:
     assert encode_info_state(state, 0, slot_config.encoding).shape == (slot_dim,)
 
 
+def test_deep_cfr_slot_aware_playability_encoding_zero_fills_empty_hand_slots() -> None:
+    config = _deep_cfr_config(
+        {"encoding": {"derived_playability": True, "slot_aware_playability": True}}
+    )
+    state = GameState.new_game(LostCitiesConfig(seed=63), seed=63)
+    state.phase = "draw"
+    state.pending_discarded_color = -1
+    state.apply_action(0)
+
+    encoded = encode_info_state(state, 0, config.encoding)
+
+    assert np.isfinite(encoded).all()
+
+
 def test_deep_cfr_trainer_uses_playability_encoding() -> None:
     config = _deep_cfr_config(
         {