diff --git a/MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs.meta b/MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs.meta
index 8094fb1d0..c3b334d51 100644
--- a/MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs.meta
+++ b/MCPForUnity/Editor/Clients/Configurators/OpenCodeConfigurator.cs.meta
@@ -1,2 +1,11 @@
 fileFormatVersion: 2
-guid: 489f99ffb7e6743e88e3203552c8b37b
\ No newline at end of file
+guid: 489f99ffb7e6743e88e3203552c8b37b
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/MCPForUnity/Editor/Constants/EditorPrefKeys.cs b/MCPForUnity/Editor/Constants/EditorPrefKeys.cs
index a6e81b4ac..42bfac2dd 100644
--- a/MCPForUnity/Editor/Constants/EditorPrefKeys.cs
+++ b/MCPForUnity/Editor/Constants/EditorPrefKeys.cs
@@ -28,6 +28,7 @@ internal static class EditorPrefKeys
         internal const string WebSocketUrlOverride = "MCPForUnity.WebSocketUrl";
         internal const string GitUrlOverride = "MCPForUnity.GitUrlOverride";
         internal const string DevModeForceServerRefresh = "MCPForUnity.DevModeForceServerRefresh";
+        internal const string UseTestPyPI = "MCPForUnity.UseTestPyPI";
         internal const string ProjectScopedToolsLocalHttp = "MCPForUnity.ProjectScopedTools.LocalHttp";
 
         internal const string PackageDeploySourcePath = "MCPForUnity.PackageDeploy.SourcePath";
diff --git a/MCPForUnity/Editor/Helpers/ConfigJsonBuilder.cs b/MCPForUnity/Editor/Helpers/ConfigJsonBuilder.cs
index dd00d73d0..489e9a070 100644
--- a/MCPForUnity/Editor/Helpers/ConfigJsonBuilder.cs
+++ b/MCPForUnity/Editor/Helpers/ConfigJsonBuilder.cs
@@ -2,8 +2,8 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using MCPForUnity.Editor.Constants;
 using MCPForUnity.Editor.Clients.Configurators;
+using MCPForUnity.Editor.Constants;
 using MCPForUnity.Editor.Helpers;
 using MCPForUnity.Editor.Models;
 using Newtonsoft.Json;
@@ -170,7 +170,19 @@ private static IList<string> BuildUvxArgs(string fromUrl, string packageName)
                 args.Add("--no-cache");
                 args.Add("--refresh");
             }
-            if (!string.IsNullOrEmpty(fromUrl))
+
+            // TestPyPI mode: use test.pypi.org as the default index for pre-release testing
+            // When using TestPyPI, don't pin version since TestPyPI versions may differ from PyPI
+            bool useTestPyPI = EditorPrefs.GetBool(EditorPrefKeys.UseTestPyPI, false);
+            if (useTestPyPI)
+            {
+                args.Add("--default-index");
+                args.Add("https://test.pypi.org/simple/");
+                // Use unversioned package name to get latest from TestPyPI
+                args.Add("--from");
+                args.Add("mcpforunityserver");
+            }
+            else if (!string.IsNullOrEmpty(fromUrl))
             {
                 args.Add("--from");
                 args.Add(fromUrl);
diff --git a/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.cs b/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.cs
index 26f610167..cc5d1defb 100644
--- a/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.cs
+++ b/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.cs
@@ -26,6 +26,7 @@ public class McpAdvancedSection
         private Button clearGitUrlButton;
         private Toggle debugLogsToggle;
         private Toggle devModeForceRefreshToggle;
+        private Toggle useTestPyPIToggle;
         private TextField deploySourcePath;
         private Button browseDeploySourceButton;
         private Button clearDeploySourceButton;
@@ -64,6 +65,7 @@ private void CacheUIElements()
             clearGitUrlButton = Root.Q<Button>("clear-git-url-button");
             debugLogsToggle = Root.Q<Toggle>("debug-logs-toggle");
             devModeForceRefreshToggle = Root.Q<Toggle>("dev-mode-force-refresh-toggle");
+            useTestPyPIToggle = Root.Q<Toggle>("use-testpypi-toggle");
             deploySourcePath = Root.Q<TextField>("deploy-source-path");
             browseDeploySourceButton = Root.Q<Button>("browse-deploy-source-button");
             clearDeploySourceButton = Root.Q<Button>("clear-deploy-source-button");
@@ -98,6 +100,13 @@ private void InitializeUI()
                 if (forceRefreshLabel != null)
                     forceRefreshLabel.tooltip = devModeForceRefreshToggle.tooltip;
             }
+            if (useTestPyPIToggle != null)
+            {
+                useTestPyPIToggle.tooltip = "When enabled, uvx will use TestPyPI (test.pypi.org) instead of PyPI to fetch the server package. Useful for testing pre-release versions.";
+                var testPyPILabel = useTestPyPIToggle?.parent?.Q<Label>();
+                if (testPyPILabel != null)
+                    testPyPILabel.tooltip = useTestPyPIToggle.tooltip;
+            }
             if (testConnectionButton != null)
                 testConnectionButton.tooltip = "Test the connection between Unity and the MCP server.";
             if (deploySourcePath != null)
@@ -128,6 +137,7 @@ private void InitializeUI()
             McpLog.SetDebugLoggingEnabled(debugEnabled);
 
             devModeForceRefreshToggle.value = EditorPrefs.GetBool(EditorPrefKeys.DevModeForceServerRefresh, false);
+            useTestPyPIToggle.value = EditorPrefs.GetBool(EditorPrefKeys.UseTestPyPI, false);
             UpdatePathOverrides();
             UpdateDeploymentSection();
         }
@@ -172,6 +182,12 @@ private void RegisterCallbacks()
                 OnHttpServerCommandUpdateRequested?.Invoke();
             });
 
+            useTestPyPIToggle.RegisterValueChangedCallback(evt =>
+            {
+                EditorPrefs.SetBool(EditorPrefKeys.UseTestPyPI, evt.newValue);
+                OnHttpServerCommandUpdateRequested?.Invoke();
+            });
+
             deploySourcePath.RegisterValueChangedCallback(evt =>
             {
                 string path = evt.newValue?.Trim();
@@ -274,6 +290,7 @@ public void UpdatePathOverrides()
             gitUrlOverride.value = EditorPrefs.GetString(EditorPrefKeys.GitUrlOverride, "");
             debugLogsToggle.value = EditorPrefs.GetBool(EditorPrefKeys.DebugLogs, false);
             devModeForceRefreshToggle.value = EditorPrefs.GetBool(EditorPrefKeys.DevModeForceServerRefresh, false);
+            useTestPyPIToggle.value = EditorPrefs.GetBool(EditorPrefKeys.UseTestPyPI, false);
             UpdateDeploymentSection();
         }
 
diff --git a/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.uxml b/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.uxml
index 50b3412c0..90a9b214a 100644
--- a/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.uxml
+++ b/MCPForUnity/Editor/Windows/Components/Advanced/McpAdvancedSection.uxml
@@ -41,6 +41,11 @@
                 <ui:Toggle name="dev-mode-force-refresh-toggle" class="setting-toggle" />
             </ui:VisualElement>
 
+            <ui:VisualElement class="setting-row">
+                <ui:Label text="Use TestPyPI:" class="setting-label" />
+                <ui:Toggle name="use-testpypi-toggle" class="setting-toggle" />
+            </ui:VisualElement>
+
             <ui:VisualElement class="override-row" style="margin-top: 8px;">
                 <ui:Label text="Package Source:" class="override-label" />
             </ui:VisualElement>