diff --git a/controllers/shepherd_dog/shepherd_dog.py b/controllers/shepherd_dog/shepherd_dog.py
index 2332478..a15ea7e 100644
--- a/controllers/shepherd_dog/shepherd_dog.py
+++ b/controllers/shepherd_dog/shepherd_dog.py
@@ -269,9 +269,19 @@ timestep = int(robot.getBasicTimeStep())
 
 # Multi-shepherd axis split. When the launcher creates two dog instances
 # it sets each robot's customData to "axis=x" or "axis=y"; the controller
-# then masks the off-axis component of every action so the two dogs
-# share the herding workload along orthogonal axes (one closes flank
-# distance in x, the other in y). customData empty = single-dog mode.
+# then attenuates the off-axis component of every action so the two
+# dogs share the herding workload along orthogonal axes. customData
+# empty = single-dog mode (no masking).
+#
+# HERDING_AXIS_LEAK controls how strict the mask is:
+#   0.0 → hard mask (off-axis component zeroed; pure axis-split)
+#   1.0 → no mask (both dogs run full action; equivalent to NDOGS=2
+#                  without axis assignment)
+# Defaults to 0.3 — empirically the 100/0 strict mask deadlocks once
+# both dogs reach their drive standoff (the Strömbom target shrinks
+# and each dog has only one degree of freedom). A small leak keeps
+# pressure on the flock while preserving the "one dog leads each
+# axis" coordination story.
 _AXIS_TAG = (robot.getCustomData() or "").strip().lower()
 if _AXIS_TAG.startswith("axis="):
     DOG_AXIS = _AXIS_TAG[5:]
@@ -280,8 +290,14 @@ if _AXIS_TAG.startswith("axis="):
         DOG_AXIS = None
 else:
     DOG_AXIS = None
+try:
+    AXIS_LEAK = float(os.environ.get("HERDING_AXIS_LEAK")
+                      or _runtime_cfg.get("HERDING_AXIS_LEAK", "0.3"))
+except ValueError:
+    AXIS_LEAK = 0.3
+AXIS_LEAK = max(0.0, min(1.0, AXIS_LEAK))
 DOG_NAME = robot.getName()
-print(f"[dog] name={DOG_NAME}  axis={DOG_AXIS}")
+print(f"[dog] name={DOG_NAME}  axis={DOG_AXIS}  leak={AXIS_LEAK:.2f}")
 
 if DRIVE_MODE == "mecanum":
     fl_motor = robot.getDevice("front left wheel motor")
@@ -483,12 +499,14 @@ while robot.step(timestep) != -1:
     # Near-sheep speed modulation (shared by every mode).
     vx, vy = modulate_speed(vx, vy, dog_xy, sheep_positions)
 
-    # Axis-split mask for the dual-dog setup: this dog only commits to
-    # its assigned axis (x or y) so its partner covers the other.
+    # Axis-split mask for the dual-dog setup: this dog leads its
+    # assigned axis (full gain) and contributes AXIS_LEAK on the
+    # off-axis. With LEAK=0 the mask is strict; with LEAK=1 the dogs
+    # run identical full-power policies.
     if DOG_AXIS == "x":
-        vy = 0.0
+        vy *= AXIS_LEAK
     elif DOG_AXIS == "y":
-        vx = 0.0
+        vx *= AXIS_LEAK
 
     # EMA smoothing — kills frame-to-frame action jitter.
     if DRIVE_MODE == "mecanum":
diff --git a/tools/run_webots.sh b/tools/run_webots.sh
index fc473ed..515a1b6 100755
--- a/tools/run_webots.sh
+++ b/tools/run_webots.sh
@@ -230,6 +230,7 @@ HERDING_DRIVE=$DRIVE
 HERDING_WORLD=$WORLD
 HERDING_LIDAR=$LIDAR_VARIANT
 HERDING_NDOGS=$NDOGS
+HERDING_AXIS_LEAK=${HERDING_AXIS_LEAK:-0.3}
 HERDING_USE_GT=${HERDING_USE_GT:-0}
 EOF