diff --git a/Tests/Runtime/AgentDispatcherTest.cs b/Tests/Runtime/AgentDispatcherTest.cs
index 0c39324..cb5f19b 100644
--- a/Tests/Runtime/AgentDispatcherTest.cs
+++ b/Tests/Runtime/AgentDispatcherTest.cs
@@ -9,6 +9,7 @@
 using Cysharp.Threading.Tasks.Triggers;
 using DeNA.Anjin.Agents;
 using DeNA.Anjin.Settings;
+using DeNA.Anjin.TestDoubles;
 using DeNA.Anjin.Utilities;
 using NUnit.Framework;
 using UnityEngine;
@@ -50,11 +51,11 @@ private static AutopilotSettings CreateAutopilotSettings()
             return testSettings;
         }
 
-        private static DoNothingAgent CreateDoNothingAgent(string name = nameof(DoNothingAgent))
+        private static SpyAliveCountAgent CreateSpyAliveCountAgent(string name = nameof(DoNothingAgent))
         {
-            var doNothingAgent = ScriptableObject.CreateInstance<DoNothingAgent>();
-            doNothingAgent.name = name;
-            return doNothingAgent;
+            var agent = ScriptableObject.CreateInstance<SpyAliveCountAgent>();
+            agent.name = name;
+            return agent;
         }
 
         private void SetUpDispatcher(AutopilotSettings settings)
@@ -81,12 +82,6 @@ private static async UniTask<Scene> LoadTestSceneAsync(string path, LoadSceneMod
             return scene;
         }
 
-        private static IEnumerable<string> FindAliveAgentNames()
-        {
-            return Object.FindObjectsOfType<AsyncDestroyTrigger>().Select(x => x.name);
-            // Note: AsyncDestroyTrigger is a component attached to the GameObject when binding agent by GetCancellationTokenOnDestroy.
-        }
-
         [Test]
         public async Task DispatchByScene_DispatchAgentBySceneAgentMaps()
         {
@@ -94,14 +89,15 @@ public async Task DispatchByScene_DispatchAgentBySceneAgentMaps()
             var settings = CreateAutopilotSettings();
             settings.sceneAgentMaps.Add(new SceneAgentMap
             {
-                scenePath = TestScenePath, agent = CreateDoNothingAgent(AgentName)
+                scenePath = TestScenePath, agent = CreateSpyAliveCountAgent(AgentName)
             });
             SetUpDispatcher(settings);
 
             await LoadTestSceneAsync(TestScenePath);
 
-            var actual = FindAliveAgentNames();
-            Assert.That(actual, Is.EquivalentTo(new[] { AgentName }));
+            var gameObject = GameObject.Find(AgentName);
+            Assert.That(gameObject, Is.Not.Null);
+            Assert.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(1));
         }
 
         [Test]
@@ -109,13 +105,14 @@ public async Task DispatchByScene_DispatchFallbackAgent()
         {
             const string AgentName = "Fallback Agent";
             var settings = CreateAutopilotSettings();
-            settings.fallbackAgent = CreateDoNothingAgent(AgentName);
+            settings.fallbackAgent = CreateSpyAliveCountAgent(AgentName);
             SetUpDispatcher(settings);
 
             await LoadTestSceneAsync(TestScenePath);
 
-            var actual = FindAliveAgentNames();
-            Assert.That(actual, Is.EquivalentTo(new[] { AgentName }));
+            var gameObject = GameObject.Find(AgentName);
+            Assert.That(gameObject, Is.Not.Null);
+            Assert.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(1));
         }
 
         [Test]
@@ -126,9 +123,8 @@ public async Task DispatchByScene_NoSceneAgentMapsAndFallbackAgent_AgentIsNotDis
 
             await LoadTestSceneAsync(TestScenePath);
 
-            var actual = FindAliveAgentNames();
-            Assert.That(actual, Is.Empty);
             LogAssert.Expect(LogType.Warning, "Agent not found by scene: Buttons");
+            Assert.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(0));
         }
 
         [Test]
@@ -136,13 +132,14 @@ public async Task DispatchByScene_DispatchObserverAgent()
         {
             const string AgentName = "Observer Agent";
             var settings = CreateAutopilotSettings();
-            settings.observerAgent = CreateDoNothingAgent(AgentName);
+            settings.observerAgent = CreateSpyAliveCountAgent(AgentName);
             SetUpDispatcher(settings);
 
             await LoadTestSceneAsync(TestScenePath);
 
-            var actual = FindAliveAgentNames();
-            Assert.That(actual, Is.EquivalentTo(new[] { AgentName }));
+            var gameObject = GameObject.Find(AgentName);
+            Assert.That(gameObject, Is.Not.Null);
+            Assert.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(1));
         }
 
         [Test]
@@ -152,22 +149,19 @@ public async Task DispatchByScene_ReActivateScene_NotCreateDuplicateAgents()
             var settings = CreateAutopilotSettings();
             settings.sceneAgentMaps.Add(new SceneAgentMap
             {
-                scenePath = TestScenePath, agent = CreateDoNothingAgent(AgentName)
+                scenePath = TestScenePath, agent = CreateSpyAliveCountAgent(AgentName)
             });
             SetUpDispatcher(settings);
 
             var scene = await LoadTestSceneAsync(TestScenePath);
-
-            var agents = FindAliveAgentNames();
-            Assume.That(agents, Is.EquivalentTo(new[] { AgentName }));
+            Assume.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(1));
 
             var additiveScene = await LoadTestSceneAsync(TestScenePath2, LoadSceneMode.Additive);
             SceneManager.SetActiveScene(additiveScene);
 
             SceneManager.SetActiveScene(scene); // Re-activate
 
-            var actual = FindAliveAgentNames();
-            Assert.That(actual, Is.EquivalentTo(new[] { AgentName }));
+            Assert.That(SpyAliveCountAgent.AliveInstances, Is.EqualTo(1)); // Not create duplicate agents
         }
     }
 }
diff --git a/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs b/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs
new file mode 100644
index 0000000..1f449f0
--- /dev/null
+++ b/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs
@@ -0,0 +1,33 @@
+// Copyright (c) 2023-2024 DeNA Co., Ltd.
+// This software is released under the MIT License.
+
+using System.Threading;
+using Cysharp.Threading.Tasks;
+using DeNA.Anjin.Agents;
+using UnityEngine;
+
+namespace DeNA.Anjin.TestDoubles
+{
+    /// <summary>
+    /// Spy agent that count the number of alive instances.
+    /// </summary>
+    [AddComponentMenu("")]
+    // ReSharper disable once RequiredBaseTypesIsNotInherited
+    public class SpyAliveCountAgent : AbstractAgent
+    {
+        public static int AliveInstances { get; private set; }
+
+        public override async UniTask Run(CancellationToken token)
+        {
+            AliveInstances++;
+            try
+            {
+                await UniTask.WaitWhile(() => true, cancellationToken: token); // Wait indefinitely
+            }
+            finally
+            {
+                AliveInstances--;
+            }
+        }
+    }
+}
diff --git a/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs.meta b/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs.meta
new file mode 100644
index 0000000..d169139
--- /dev/null
+++ b/Tests/Runtime/TestDoubles/SpyAliveCountAgent.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: a45a8161cc09438b9b33c7a670e39335
+timeCreated: 1713821110
\ No newline at end of file