diff --git a/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/InputSimulationRunInBackgroundScope.cs b/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/InputSimulationRunInBackgroundScope.cs
index c3a0380bc6..340e6f778f 100644
--- a/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/InputSimulationRunInBackgroundScope.cs
+++ b/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/InputSimulationRunInBackgroundScope.cs
@@ -1,6 +1,8 @@
 #nullable enable
 using System;
 
+using io.github.hatayama.UnityCliLoop.ToolContracts;
+
 namespace io.github.hatayama.UnityCliLoop.FirstPartyTools
 {
     /// <summary>
@@ -29,6 +31,12 @@ public static InputSimulationRunInBackgroundScope Enable()
 
         public void Dispose()
         {
+            // Precondition: Application.runInBackground is main-thread-only, so callers resuming
+            // from ConfigureAwait(false) continuations must switch back to the main thread first.
+            UnityEngine.Debug.Assert(
+                MainThreadSwitcher.IsMainThread,
+                "InputSimulationRunInBackgroundScope.Dispose must be called on the main thread.");
+
             if (_isDisposed)
             {
                 return;
diff --git a/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/UnityCLILoop.FirstPartyTools.Common.InputSimulation.Editor.asmdef b/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/UnityCLILoop.FirstPartyTools.Common.InputSimulation.Editor.asmdef
index 830a323f36..763c0aa031 100644
--- a/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/UnityCLILoop.FirstPartyTools.Common.InputSimulation.Editor.asmdef
+++ b/Packages/src/Editor/FirstPartyTools/Common/InputSimulation/UnityCLILoop.FirstPartyTools.Common.InputSimulation.Editor.asmdef
@@ -1,7 +1,9 @@
 {
     "name": "UnityCLILoop.FirstPartyTools.Common.InputSimulation.Editor",
     "rootNamespace": "io.github.hatayama.UnityCliLoop.FirstPartyTools",
-    "references": [],
+    "references": [
+        "GUID:fc3fd32eddbee40e39c2d76dc184957b"
+    ],
     "includePlatforms": [
         "Editor"
     ],
diff --git a/Packages/src/Editor/FirstPartyTools/SimulateKeyboard/SimulateKeyboardUseCase.cs b/Packages/src/Editor/FirstPartyTools/SimulateKeyboard/SimulateKeyboardUseCase.cs
index 3c539fe5ad..f467917a12 100644
--- a/Packages/src/Editor/FirstPartyTools/SimulateKeyboard/SimulateKeyboardUseCase.cs
+++ b/Packages/src/Editor/FirstPartyTools/SimulateKeyboard/SimulateKeyboardUseCase.cs
@@ -104,49 +104,59 @@ public async Task<SimulateKeyboardResponse> ExecuteAsync(
                 correlationId: correlationId
             );
 
-            using InputSimulationRunInBackgroundScope runInBackgroundScope = InputSimulationRunInBackgroundScope.Enable();
-
-            EnsureOverlayExists();
+            // Why not `using`: the executor awaits below use ConfigureAwait(false), so this method
+            // can resume on a thread-pool thread. Application.runInBackground is main-thread-only,
+            // so the scope must be disposed after switching back to the main thread.
+            InputSimulationRunInBackgroundScope runInBackgroundScope = InputSimulationRunInBackgroundScope.Enable();
+            try
+            {
+                EnsureOverlayExists();
 
-            SimulateKeyboardResponse response;
+                SimulateKeyboardResponse response;
 
-            switch (parameters.Action)
+                switch (parameters.Action)
+                {
+                    case UnityCliLoopKeyboardAction.Press:
+                        response = await KeyboardInputActionExecutor.ExecutePress(
+                            keyboard,
+                            key,
+                            parameters.Duration,
+                            ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopKeyboardAction.KeyDown:
+                        response = await KeyboardInputActionExecutor.ExecuteKeyDown(keyboard, key, ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopKeyboardAction.KeyUp:
+                        response = await KeyboardInputActionExecutor.ExecuteKeyUp(keyboard, key, ct).ConfigureAwait(false);
+                        break;
+
+                    default:
+                        // Only reachable when an out-of-range enum value is cast from an integer;
+                        // surface as a Success=false response so the CLI treats it as a normal validation failure.
+                        return new SimulateKeyboardResponse
+                        {
+                            Success = false,
+                            Message = $"Unknown keyboard action: {parameters.Action}",
+                            Action = parameters.Action.ToString()
+                        };
+                }
+
+                VibeLogger.LogInfo(
+                    "simulate_keyboard_complete",
+                    $"Keyboard simulation completed: {response.Message}",
+                    new { Action = parameters.Action.ToString(), Success = response.Success },
+                    correlationId: correlationId
+                );
+
+                return response;
+            }
+            finally
             {
-                case UnityCliLoopKeyboardAction.Press:
-                    response = await KeyboardInputActionExecutor.ExecutePress(
-                        keyboard,
-                        key,
-                        parameters.Duration,
-                        ct).ConfigureAwait(false);
-                    break;
-
-                case UnityCliLoopKeyboardAction.KeyDown:
-                    response = await KeyboardInputActionExecutor.ExecuteKeyDown(keyboard, key, ct).ConfigureAwait(false);
-                    break;
-
-                case UnityCliLoopKeyboardAction.KeyUp:
-                    response = await KeyboardInputActionExecutor.ExecuteKeyUp(keyboard, key, ct).ConfigureAwait(false);
-                    break;
-
-                default:
-                    // Only reachable when an out-of-range enum value is cast from an integer;
-                    // surface as a Success=false response so the CLI treats it as a normal validation failure.
-                    return new SimulateKeyboardResponse
-                    {
-                        Success = false,
-                        Message = $"Unknown keyboard action: {parameters.Action}",
-                        Action = parameters.Action.ToString()
-                    };
+                await InputSystemUpdateHelper.SwitchToMainThreadIfNeeded(CancellationToken.None);
+                runInBackgroundScope.Dispose();
             }
-
-            VibeLogger.LogInfo(
-                "simulate_keyboard_complete",
-                $"Keyboard simulation completed: {response.Message}",
-                new { Action = parameters.Action.ToString(), Success = response.Success },
-                correlationId: correlationId
-            );
-
-            return response;
 #endif
         }
 
diff --git a/Packages/src/Editor/FirstPartyTools/SimulateMouseInput/SimulateMouseInputUseCase.cs b/Packages/src/Editor/FirstPartyTools/SimulateMouseInput/SimulateMouseInputUseCase.cs
index ef3de4fe4a..9bc0fa565d 100644
--- a/Packages/src/Editor/FirstPartyTools/SimulateMouseInput/SimulateMouseInputUseCase.cs
+++ b/Packages/src/Editor/FirstPartyTools/SimulateMouseInput/SimulateMouseInputUseCase.cs
@@ -97,46 +97,56 @@ public async Task<SimulateMouseInputResponse> ExecuteAsync(
                 correlationId: correlationId
             );
 
-            using InputSimulationRunInBackgroundScope runInBackgroundScope = InputSimulationRunInBackgroundScope.Enable();
-
-            EnsureOverlayExists();
-
-            SimulateMouseInputResponse response;
-
-            switch (parameters.Action)
+            // Why not `using`: the executor awaits below use ConfigureAwait(false), so this method
+            // can resume on a thread-pool thread. Application.runInBackground is main-thread-only,
+            // so the scope must be disposed after switching back to the main thread.
+            InputSimulationRunInBackgroundScope runInBackgroundScope = InputSimulationRunInBackgroundScope.Enable();
+            try
             {
-                case UnityCliLoopMouseInputAction.Click:
-                    response = await MouseInputPressActionExecutor.ExecuteClick(mouse, parameters, ct).ConfigureAwait(false);
-                    break;
-
-                case UnityCliLoopMouseInputAction.LongPress:
-                    response = await MouseInputPressActionExecutor.ExecuteLongPress(mouse, parameters, ct).ConfigureAwait(false);
-                    break;
+                EnsureOverlayExists();
 
-                case UnityCliLoopMouseInputAction.MoveDelta:
-                    response = await MouseInputMotionActionExecutor.ExecuteMoveDelta(mouse, parameters, ct).ConfigureAwait(false);
-                    break;
+                SimulateMouseInputResponse response;
 
-                case UnityCliLoopMouseInputAction.Scroll:
-                    response = await MouseInputMotionActionExecutor.ExecuteScroll(mouse, parameters, ct).ConfigureAwait(false);
-                    break;
-
-                case UnityCliLoopMouseInputAction.SmoothDelta:
-                    response = await MouseInputMotionActionExecutor.ExecuteSmoothDelta(mouse, parameters, ct).ConfigureAwait(false);
-                    break;
-
-                default:
-                    throw new ArgumentException($"Unknown mouse input action: {parameters.Action}");
+                switch (parameters.Action)
+                {
+                    case UnityCliLoopMouseInputAction.Click:
+                        response = await MouseInputPressActionExecutor.ExecuteClick(mouse, parameters, ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopMouseInputAction.LongPress:
+                        response = await MouseInputPressActionExecutor.ExecuteLongPress(mouse, parameters, ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopMouseInputAction.MoveDelta:
+                        response = await MouseInputMotionActionExecutor.ExecuteMoveDelta(mouse, parameters, ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopMouseInputAction.Scroll:
+                        response = await MouseInputMotionActionExecutor.ExecuteScroll(mouse, parameters, ct).ConfigureAwait(false);
+                        break;
+
+                    case UnityCliLoopMouseInputAction.SmoothDelta:
+                        response = await MouseInputMotionActionExecutor.ExecuteSmoothDelta(mouse, parameters, ct).ConfigureAwait(false);
+                        break;
+
+                    default:
+                        throw new ArgumentException($"Unknown mouse input action: {parameters.Action}");
+                }
+
+                VibeLogger.LogInfo(
+                    "simulate_mouse_input_complete",
+                    $"Mouse input simulation completed: {response.Message}",
+                    new { Action = parameters.Action.ToString(), Success = response.Success },
+                    correlationId: correlationId
+                );
+
+                return response;
+            }
+            finally
+            {
+                await InputSystemUpdateHelper.SwitchToMainThreadIfNeeded(CancellationToken.None);
+                runInBackgroundScope.Dispose();
             }
-
-            VibeLogger.LogInfo(
-                "simulate_mouse_input_complete",
-                $"Mouse input simulation completed: {response.Message}",
-                new { Action = parameters.Action.ToString(), Success = response.Success },
-                correlationId: correlationId
-            );
-
-            return response;
 #endif
         }