diff --git a/services/inputflinger/UnwantedInteractionBlocker.cpp b/services/inputflinger/UnwantedInteractionBlocker.cpp
index fc8dfe6..ec41025 100644
--- a/services/inputflinger/UnwantedInteractionBlocker.cpp
+++ b/services/inputflinger/UnwantedInteractionBlocker.cpp
@@ -77,8 +77,7 @@
 }
 
 static bool isFromTouchscreen(int32_t source) {
-    return isFromSource(source, AINPUT_SOURCE_TOUCHSCREEN) &&
-            !isFromSource(source, AINPUT_SOURCE_STYLUS);
+    return isFromSource(source, AINPUT_SOURCE_TOUCHSCREEN);
 }
 
 static ::base::TimeTicks toChromeTimestamp(nsecs_t eventTime) {
@@ -142,23 +141,6 @@
     return AMOTION_EVENT_ACTION_MOVE;
 }
 
-/**
- * Remove the data for the provided pointers from the args. The pointers are identified by their
- * pointerId, not by the index inside the array.
- * Return the new NotifyMotionArgs struct that has the remaining pointers.
- * The only fields that may be different in the returned args from the provided args are:
- *     - action
- *     - pointerCount
- *     - pointerProperties
- *     - pointerCoords
- * Action might change because it contains a pointer index. If another pointer is removed, the
- * active pointer index would be shifted.
- * Do not call this function for events with POINTER_UP or POINTER_DOWN events when removed pointer
- * id is the acting pointer id.
- *
- * @param args the args from which the pointers should be removed
- * @param pointerIds the pointer ids of the pointers that should be removed
- */
 NotifyMotionArgs removePointerIds(const NotifyMotionArgs& args,
                                   const std::set<int32_t>& pointerIds) {
     const uint8_t actionIndex = MotionEvent::getActionIndex(args.action);
@@ -204,6 +186,26 @@
     return newArgs;
 }
 
+/**
+ * Remove stylus pointers from the provided NotifyMotionArgs.
+ *
+ * Return NotifyMotionArgs where the stylus pointers have been removed.
+ * If this results in removal of the active pointer, then return nullopt.
+ */
+static std::optional<NotifyMotionArgs> removeStylusPointerIds(const NotifyMotionArgs& args) {
+    std::set<int32_t> stylusPointerIds;
+    for (uint32_t i = 0; i < args.pointerCount; i++) {
+        if (args.pointerProperties[i].toolType == AMOTION_EVENT_TOOL_TYPE_STYLUS) {
+            stylusPointerIds.insert(args.pointerProperties[i].id);
+        }
+    }
+    NotifyMotionArgs withoutStylusPointers = removePointerIds(args, stylusPointerIds);
+    if (withoutStylusPointers.pointerCount == 0 || withoutStylusPointers.action == ACTION_UNKNOWN) {
+        return std::nullopt;
+    }
+    return withoutStylusPointers;
+}
+
 std::optional<AndroidPalmFilterDeviceInfo> createPalmFilterDeviceInfo(
         const InputDeviceInfo& deviceInfo) {
     if (!isFromTouchscreen(deviceInfo.getSources())) {
@@ -678,7 +680,15 @@
 
     std::set<int32_t> oldSuppressedIds;
     std::swap(oldSuppressedIds, mSuppressedPointerIds);
-    mSuppressedPointerIds = detectPalmPointers(args);
+
+    std::optional<NotifyMotionArgs> touchOnlyArgs = removeStylusPointerIds(args);
+    if (touchOnlyArgs) {
+        mSuppressedPointerIds = detectPalmPointers(*touchOnlyArgs);
+    } else {
+        // This is a stylus-only event.
+        // We can skip this event and just keep the suppressed pointer ids the same as before.
+        mSuppressedPointerIds = oldSuppressedIds;
+    }
 
     std::vector<NotifyMotionArgs> argsWithoutUnwantedPointers =
             cancelSuppressedPointers(args, oldSuppressedIds, mSuppressedPointerIds);
diff --git a/services/inputflinger/UnwantedInteractionBlocker.h b/services/inputflinger/UnwantedInteractionBlocker.h
index a176a98..5d0dde8 100644
--- a/services/inputflinger/UnwantedInteractionBlocker.h
+++ b/services/inputflinger/UnwantedInteractionBlocker.h
@@ -43,6 +43,25 @@
 
 static constexpr int32_t ACTION_UNKNOWN = -1;
 
+/**
+ * Remove the data for the provided pointers from the args. The pointers are identified by their
+ * pointerId, not by the index inside the array.
+ * Return the new NotifyMotionArgs struct that has the remaining pointers.
+ * The only fields that may be different in the returned args from the provided args are:
+ *     - action
+ *     - pointerCount
+ *     - pointerProperties
+ *     - pointerCoords
+ * Action might change because it contains a pointer index. If another pointer is removed, the
+ * active pointer index would be shifted.
+ *
+ * If the active pointer id is removed (for example, for events like
+ * POINTER_UP or POINTER_DOWN), then the action is set to ACTION_UNKNOWN. It is up to the caller
+ * to set the action appropriately after the call.
+ *
+ * @param args the args from which the pointers should be removed
+ * @param pointerIds the pointer ids of the pointers that should be removed
+ */
 NotifyMotionArgs removePointerIds(const NotifyMotionArgs& args,
                                   const std::set<int32_t>& pointerIds);
 
diff --git a/services/inputflinger/tests/UnwantedInteractionBlocker_test.cpp b/services/inputflinger/tests/UnwantedInteractionBlocker_test.cpp
index 9313a45..29fa001 100644
--- a/services/inputflinger/tests/UnwantedInteractionBlocker_test.cpp
+++ b/services/inputflinger/tests/UnwantedInteractionBlocker_test.cpp
@@ -66,6 +66,10 @@
     return result;
 }
 
+MATCHER_P(WithFlags, flags, "MotionEvent with specified flags") {
+    return arg.flags == flags;
+}
+
 static nsecs_t toNs(std::chrono::nanoseconds duration) {
     return duration.count();
 }
@@ -616,6 +620,90 @@
     mTestListener.assertNotifyMotionWasCalled(WithAction(CANCEL));
 }
 
+/**
+ * Send a stylus event that would have triggered the heuristic palm detector if it were a touch
+ * event. However, since it's a stylus event, it should propagate without being canceled through
+ * the blocker.
+ * This is similar to `HeuristicFilterWorks` test, but for stylus tool.
+ */
+TEST_F(UnwantedInteractionBlockerTest, StylusIsNotBlocked) {
+    InputDeviceInfo info = generateTestDeviceInfo();
+    info.addSource(AINPUT_SOURCE_STYLUS);
+    mBlocker->notifyInputDevicesChanged({info});
+    NotifyMotionArgs args1 = generateMotionArgs(0 /*downTime*/, 0 /*eventTime*/, DOWN, {{1, 2, 3}});
+    args1.pointerProperties[0].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args1);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(DOWN));
+
+    // Move the stylus, setting large TOUCH_MAJOR/TOUCH_MINOR dimensions
+    NotifyMotionArgs args2 =
+            generateMotionArgs(0 /*downTime*/, RESAMPLE_PERIOD, MOVE, {{4, 5, 200}});
+    args2.pointerProperties[0].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args2);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(MOVE));
+
+    // Lift up the stylus. If it were a touch event, this would force the model to decide on whether
+    // it's a palm.
+    NotifyMotionArgs args3 =
+            generateMotionArgs(0 /*downTime*/, 2 * RESAMPLE_PERIOD, UP, {{4, 5, 200}});
+    args3.pointerProperties[0].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args3);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(UP));
+}
+
+/**
+ * Send a mixed touch and stylus event.
+ * The touch event goes first, and is a palm. The stylus event goes down after.
+ * Stylus event should continue to work even after touch is detected as a palm.
+ */
+TEST_F(UnwantedInteractionBlockerTest, TouchIsBlockedWhenMixedWithStylus) {
+    InputDeviceInfo info = generateTestDeviceInfo();
+    info.addSource(AINPUT_SOURCE_STYLUS);
+    mBlocker->notifyInputDevicesChanged({info});
+
+    // Touch down
+    NotifyMotionArgs args1 = generateMotionArgs(0 /*downTime*/, 0 /*eventTime*/, DOWN, {{1, 2, 3}});
+    mBlocker->notifyMotion(&args1);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(DOWN));
+
+    // Stylus pointer down
+    NotifyMotionArgs args2 = generateMotionArgs(0 /*downTime*/, RESAMPLE_PERIOD, POINTER_1_DOWN,
+                                                {{1, 2, 3}, {10, 20, 30}});
+    args2.pointerProperties[1].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args2);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(POINTER_1_DOWN));
+
+    // Large touch oval on the next finger move
+    NotifyMotionArgs args3 = generateMotionArgs(0 /*downTime*/, 2 * RESAMPLE_PERIOD, MOVE,
+                                                {{1, 2, 300}, {11, 21, 30}});
+    args3.pointerProperties[1].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args3);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(MOVE));
+
+    // Lift up the finger pointer. It should be canceled due to the heuristic filter.
+    NotifyMotionArgs args4 = generateMotionArgs(0 /*downTime*/, 3 * RESAMPLE_PERIOD, POINTER_0_UP,
+                                                {{1, 2, 300}, {11, 21, 30}});
+    args4.pointerProperties[1].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args4);
+    mTestListener.assertNotifyMotionWasCalled(
+            AllOf(WithAction(POINTER_0_UP), WithFlags(FLAG_CANCELED)));
+
+    NotifyMotionArgs args5 =
+            generateMotionArgs(0 /*downTime*/, 4 * RESAMPLE_PERIOD, MOVE, {{12, 22, 30}});
+    args5.pointerProperties[0].id = args4.pointerProperties[1].id;
+    args5.pointerProperties[0].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args5);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(MOVE));
+
+    // Lift up the stylus pointer
+    NotifyMotionArgs args6 =
+            generateMotionArgs(0 /*downTime*/, 5 * RESAMPLE_PERIOD, UP, {{4, 5, 200}});
+    args6.pointerProperties[0].id = args4.pointerProperties[1].id;
+    args6.pointerProperties[0].toolType = AMOTION_EVENT_TOOL_TYPE_STYLUS;
+    mBlocker->notifyMotion(&args6);
+    mTestListener.assertNotifyMotionWasCalled(WithAction(UP));
+}
+
 using UnwantedInteractionBlockerTestDeathTest = UnwantedInteractionBlockerTest;
 
 /**