Open and close prefabs in the stage view + create them (#283)

* refactor: remove unused UnityEngine references from menu item classes

* Add new tools to manage a prefab, particularly, making them staged.

This might be enough, but it's possible we may have to extract some logic from ManageGameObject

* feat: add AssetPathUtility for asset path normalization and update references in ManageAsset and ManagePrefabs

* feat: add prefab management tools and register them with the MCP server

* feat: update prefab management commands to use 'prefabPath' and add 'create_from_gameobject' action

* fix: update parameter references to 'prefabPath' in ManagePrefabs and manage_prefabs tools

* fix: clarify error message for missing 'prefabPath' in create_from_gameobject command

* fix: ensure pull request triggers for unity tests workflow

* Revert "fix: ensure pull request triggers for unity tests workflow"

This reverts commit 10bfe54b5b7f3c449852b1bf1bb72f498289a1a0.

* Remove delayed execution of executing menu item, fixing #279
This brings the Unity window into focus but that seems to be a better UX for devs.
Also streamline manage_menu_item tool info, as FastMCP recommends

* docs: clarify menu item tool description with guidance to use list action first

* feat: add version update for server_version.txt in bump-version workflow

* fix: simplify error message for failed menu item execution

.github/workflows/bump-version.yml

@@ -70,6 +70,9 @@ jobs:
           echo "Updating UnityMcpBridge/UnityMcpServer~/src/pyproject.toml to $NEW_VERSION"
           sed -i '0,/^version = ".*"/s//version = "'"$NEW_VERSION"'"/' "UnityMcpBridge/UnityMcpServer~/src/pyproject.toml"
 
+          echo "Updating UnityMcpBridge/UnityMcpServer~/src/server_version.txt to $NEW_VERSION"
+          echo "$NEW_VERSION" > "UnityMcpBridge/UnityMcpServer~/src/server_version.txt"
+
       - name: Commit and push changes
         env:
           NEW_VERSION: ${{ steps.compute.outputs.new_version }}
@@ -78,7 +81,7 @@ jobs:
           set -euo pipefail
           git config user.name "GitHub Actions"
           git config user.email "actions@github.com"
-          git add UnityMcpBridge/package.json "UnityMcpBridge/UnityMcpServer~/src/pyproject.toml"
+          git add UnityMcpBridge/package.json "UnityMcpBridge/UnityMcpServer~/src/pyproject.toml" "UnityMcpBridge/UnityMcpServer~/src/server_version.txt"
           if git diff --cached --quiet; then
             echo "No version changes to commit."
           else

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManagePrefabsTests.cs

@@ -0,0 +1,255 @@
+using System.IO;
+using Newtonsoft.Json.Linq;
+using NUnit.Framework;
+using UnityEditor;
+using UnityEditor.SceneManagement;
+using UnityEngine;
+using MCPForUnity.Editor.Tools.Prefabs;
+using MCPForUnity.Editor.Tools;
+
+namespace MCPForUnityTests.Editor.Tools
+{
+    public class ManagePrefabsTests
+    {
+        private const string TempDirectory = "Assets/Temp/ManagePrefabsTests";
+
+        [SetUp]
+        public void SetUp()
+        {
+            StageUtility.GoToMainStage();
+            EnsureTempDirectoryExists();
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            StageUtility.GoToMainStage();
+        }
+
+        [OneTimeTearDown]
+        public void CleanupAll()
+        {
+            StageUtility.GoToMainStage();
+            if (AssetDatabase.IsValidFolder(TempDirectory))
+            {
+                AssetDatabase.DeleteAsset(TempDirectory);
+            }
+        }
+
+        [Test]
+        public void OpenStage_OpensPrefabInIsolation()
+        {
+            string prefabPath = CreateTestPrefab("OpenStageCube");
+
+            try
+            {
+                var openParams = new JObject
+                {
+                    ["action"] = "open_stage",
+                    ["prefabPath"] = prefabPath
+                };
+
+                var openResult = ToJObject(ManagePrefabs.HandleCommand(openParams));
+
+                Assert.IsTrue(openResult.Value<bool>("success"), "open_stage should succeed for a valid prefab.");
+
+                PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+                Assert.IsNotNull(stage, "Prefab stage should be open after open_stage.");
+                Assert.AreEqual(prefabPath, stage.assetPath, "Opened stage should match prefab path.");
+
+                var stageInfo = ToJObject(ManageEditor.HandleCommand(new JObject { ["action"] = "get_prefab_stage" }));
+                Assert.IsTrue(stageInfo.Value<bool>("success"), "get_prefab_stage should succeed when stage is open.");
+
+                var data = stageInfo["data"] as JObject;
+                Assert.IsNotNull(data, "Stage info should include data payload.");
+                Assert.IsTrue(data.Value<bool>("isOpen"));
+                Assert.AreEqual(prefabPath, data.Value<string>("assetPath"));
+            }
+            finally
+            {
+                StageUtility.GoToMainStage();
+                AssetDatabase.DeleteAsset(prefabPath);
+            }
+        }
+
+        [Test]
+        public void CloseStage_ReturnsSuccess_WhenNoStageOpen()
+        {
+            StageUtility.GoToMainStage();
+            var closeResult = ToJObject(ManagePrefabs.HandleCommand(new JObject
+            {
+                ["action"] = "close_stage"
+            }));
+
+            Assert.IsTrue(closeResult.Value<bool>("success"), "close_stage should succeed even if no stage is open.");
+        }
+
+        [Test]
+        public void CloseStage_ClosesOpenPrefabStage()
+        {
+            string prefabPath = CreateTestPrefab("CloseStageCube");
+
+            try
+            {
+                ManagePrefabs.HandleCommand(new JObject
+                {
+                    ["action"] = "open_stage",
+                    ["prefabPath"] = prefabPath
+                });
+
+                var closeResult = ToJObject(ManagePrefabs.HandleCommand(new JObject
+                {
+                    ["action"] = "close_stage"
+                }));
+
+                Assert.IsTrue(closeResult.Value<bool>("success"), "close_stage should succeed when stage is open.");
+                Assert.IsNull(PrefabStageUtility.GetCurrentPrefabStage(), "Prefab stage should be closed after close_stage.");
+            }
+            finally
+            {
+                StageUtility.GoToMainStage();
+                AssetDatabase.DeleteAsset(prefabPath);
+            }
+        }
+
+        [Test]
+        public void SaveOpenStage_SavesDirtyChanges()
+        {
+            string prefabPath = CreateTestPrefab("SaveStageCube");
+
+            try
+            {
+                ManagePrefabs.HandleCommand(new JObject
+                {
+                    ["action"] = "open_stage",
+                    ["prefabPath"] = prefabPath
+                });
+
+                PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+                Assert.IsNotNull(stage, "Stage should be open before modifying.");
+
+                stage.prefabContentsRoot.transform.localScale = new Vector3(2f, 2f, 2f);
+
+                var saveResult = ToJObject(ManagePrefabs.HandleCommand(new JObject
+                {
+                    ["action"] = "save_open_stage"
+                }));
+
+                Assert.IsTrue(saveResult.Value<bool>("success"), "save_open_stage should succeed when stage is open.");
+                Assert.IsFalse(stage.scene.isDirty, "Stage scene should not be dirty after saving.");
+
+                GameObject reloaded = AssetDatabase.LoadAssetAtPath<GameObject>(prefabPath);
+                Assert.AreEqual(new Vector3(2f, 2f, 2f), reloaded.transform.localScale, "Saved prefab asset should include changes from open stage.");
+            }
+            finally
+            {
+                StageUtility.GoToMainStage();
+                AssetDatabase.DeleteAsset(prefabPath);
+            }
+        }
+
+        [Test]
+        public void SaveOpenStage_ReturnsError_WhenNoStageOpen()
+        {
+            StageUtility.GoToMainStage();
+
+            var saveResult = ToJObject(ManagePrefabs.HandleCommand(new JObject
+            {
+                ["action"] = "save_open_stage"
+            }));
+
+            Assert.IsFalse(saveResult.Value<bool>("success"), "save_open_stage should fail when no stage is open.");
+        }
+
+        [Test]
+        public void CreateFromGameObject_CreatesPrefabAndLinksInstance()
+        {
+            EnsureTempDirectoryExists();
+            StageUtility.GoToMainStage();
+
+            string prefabPath = Path.Combine(TempDirectory, "SceneObjectSaved.prefab").Replace('\\', '/');
+            GameObject sceneObject = new GameObject("ScenePrefabSource");
+
+            try
+            {
+                var result = ToJObject(ManagePrefabs.HandleCommand(new JObject
+                {
+                    ["action"] = "create_from_gameobject",
+                    ["target"] = sceneObject.name,
+                    ["prefabPath"] = prefabPath
+                }));
+
+                Assert.IsTrue(result.Value<bool>("success"), "create_from_gameobject should succeed for a valid scene object.");
+
+                var data = result["data"] as JObject;
+                Assert.IsNotNull(data, "Response data should include prefab information.");
+
+                string savedPath = data.Value<string>("prefabPath");
+                Assert.AreEqual(prefabPath, savedPath, "Returned prefab path should match the requested path.");
+
+                GameObject prefabAsset = AssetDatabase.LoadAssetAtPath<GameObject>(savedPath);
+                Assert.IsNotNull(prefabAsset, "Prefab asset should exist at the saved path.");
+
+                int instanceId = data.Value<int>("instanceId");
+                var linkedInstance = EditorUtility.InstanceIDToObject(instanceId) as GameObject;
+                Assert.IsNotNull(linkedInstance, "Linked instance should resolve from instanceId.");
+                Assert.AreEqual(savedPath, PrefabUtility.GetPrefabAssetPathOfNearestInstanceRoot(linkedInstance), "Instance should be connected to the new prefab.");
+
+                sceneObject = linkedInstance;
+            }
+            finally
+            {
+                if (AssetDatabase.LoadAssetAtPath<UnityEngine.Object>(prefabPath) != null)
+                {
+                    AssetDatabase.DeleteAsset(prefabPath);
+                }
+
+                if (sceneObject != null)
+                {
+                    if (PrefabUtility.IsPartOfPrefabInstance(sceneObject))
+                    {
+                        PrefabUtility.UnpackPrefabInstance(
+                            sceneObject,
+                            PrefabUnpackMode.Completely,
+                            InteractionMode.AutomatedAction
+                        );
+                    }
+                    UnityEngine.Object.DestroyImmediate(sceneObject, true);
+                }
+            }
+        }
+
+        private static string CreateTestPrefab(string name)
+        {
+            EnsureTempDirectoryExists();
+
+            GameObject temp = GameObject.CreatePrimitive(PrimitiveType.Cube);
+            temp.name = name;
+
+            string path = Path.Combine(TempDirectory, name + ".prefab").Replace('\\', '/');
+            PrefabUtility.SaveAsPrefabAsset(temp, path, out bool success);
+            UnityEngine.Object.DestroyImmediate(temp);
+
+            Assert.IsTrue(success, "PrefabUtility.SaveAsPrefabAsset should succeed for test prefab.");
+            return path;
+        }
+
+        private static void EnsureTempDirectoryExists()
+        {
+            if (!AssetDatabase.IsValidFolder("Assets/Temp"))
+            {
+                AssetDatabase.CreateFolder("Assets", "Temp");
+            }
+
+            if (!AssetDatabase.IsValidFolder(TempDirectory))
+            {
+                AssetDatabase.CreateFolder("Assets/Temp", "ManagePrefabsTests");
+            }
+        }
+
+        private static JObject ToJObject(object result)
+        {
+            return result as JObject ?? JObject.FromObject(result);
+        }
+    }
+}

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManagePrefabsTests.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8e7a7e542325421ba6de4992ddb3f5db
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

UnityMcpBridge/Editor/Helpers/AssetPathUtility.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace MCPForUnity.Editor.Helpers
+{
+    /// <summary>
+    /// Provides common utility methods for working with Unity asset paths.
+    /// </summary>
+    public static class AssetPathUtility
+    {
+        /// <summary>
+        /// Normalizes a Unity asset path by ensuring forward slashes are used and that it is rooted under "Assets/".
+        /// </summary>
+        public static string SanitizeAssetPath(string path)
+        {
+            if (string.IsNullOrEmpty(path))
+            {
+                return path;
+            }
+
+            path = path.Replace('\\', '/');
+            if (!path.StartsWith("Assets/", StringComparison.OrdinalIgnoreCase))
+            {
+                return "Assets/" + path.TrimStart('/');
+            }
+
+            return path;
+        }
+    }
+}

UnityMcpBridge/Editor/Helpers/AssetPathUtility.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 1d42f5b5ea5d4d43ad1a771e14bda2a0
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

UnityMcpBridge/Editor/MCPForUnityBridge.cs

@@ -15,6 +15,7 @@ using MCPForUnity.Editor.Helpers;
 using MCPForUnity.Editor.Models;
 using MCPForUnity.Editor.Tools;
 using MCPForUnity.Editor.Tools.MenuItems;
+using MCPForUnity.Editor.Tools.Prefabs;
 
 namespace MCPForUnity.Editor
 {
@@ -1040,7 +1041,26 @@ namespace MCPForUnity.Editor
                 // Use JObject for parameters as the new handlers likely expect this
                 JObject paramsObject = command.@params ?? new JObject();
 
-                object result = CommandRegistry.GetHandler(command.type)(paramsObject);
+                // Route command based on the new tool structure from the refactor plan
+                object result = command.type switch
+                {
+                    // Maps the command type (tool name) to the corresponding handler's static HandleCommand method
+                    // Assumes each handler class has a static method named 'HandleCommand' that takes JObject parameters
+                    "manage_script" => ManageScript.HandleCommand(paramsObject),
+                    // Run scene operations on the main thread to avoid deadlocks/hangs (with diagnostics under debug flag)
+                    "manage_scene" => HandleManageScene(paramsObject)
+                        ?? throw new TimeoutException($"manage_scene timed out after {FrameIOTimeoutMs} ms on main thread"),
+                    "manage_editor" => ManageEditor.HandleCommand(paramsObject),
+                    "manage_gameobject" => ManageGameObject.HandleCommand(paramsObject),
+                    "manage_asset" => ManageAsset.HandleCommand(paramsObject),
+                    "manage_shader" => ManageShader.HandleCommand(paramsObject),
+                    "read_console" => ReadConsole.HandleCommand(paramsObject),
+                    "manage_menu_item" => ManageMenuItem.HandleCommand(paramsObject),
+                    "manage_prefabs" => ManagePrefabs.HandleCommand(paramsObject),
+                    _ => throw new ArgumentException(
+                        $"Unknown or unsupported command type: {command.type}"
+                    ),
+                };
 
                 // Standard success response format
                 var response = new { status = "success", result };

UnityMcpBridge/Editor/Tools/ManageAsset.cs

@@ -115,7 +115,7 @@ namespace MCPForUnity.Editor.Tools
         {
             if (string.IsNullOrEmpty(path))
                 return Response.Error("'path' is required for reimport.");
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(fullPath))
                 return Response.Error($"Asset not found at path: {fullPath}");
 
@@ -154,7 +154,7 @@ namespace MCPForUnity.Editor.Tools
             if (string.IsNullOrEmpty(assetType))
                 return Response.Error("'assetType' is required for create.");
 
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             string directory = Path.GetDirectoryName(fullPath);
 
             // Ensure directory exists
@@ -280,7 +280,7 @@ namespace MCPForUnity.Editor.Tools
         {
             if (string.IsNullOrEmpty(path))
                 return Response.Error("'path' is required for create_folder.");
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             string parentDir = Path.GetDirectoryName(fullPath);
             string folderName = Path.GetFileName(fullPath);
 
@@ -338,7 +338,7 @@ namespace MCPForUnity.Editor.Tools
             if (properties == null || !properties.HasValues)
                 return Response.Error("'properties' are required for modify.");
 
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(fullPath))
                 return Response.Error($"Asset not found at path: {fullPath}");
 
@@ -495,7 +495,7 @@ namespace MCPForUnity.Editor.Tools
         {
             if (string.IsNullOrEmpty(path))
                 return Response.Error("'path' is required for delete.");
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(fullPath))
                 return Response.Error($"Asset not found at path: {fullPath}");
 
@@ -526,7 +526,7 @@ namespace MCPForUnity.Editor.Tools
             if (string.IsNullOrEmpty(path))
                 return Response.Error("'path' is required for duplicate.");
 
-            string sourcePath = SanitizeAssetPath(path);
+            string sourcePath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(sourcePath))
                 return Response.Error($"Source asset not found at path: {sourcePath}");
 
@@ -538,7 +538,7 @@ namespace MCPForUnity.Editor.Tools
             }
             else
             {
-                destPath = SanitizeAssetPath(destinationPath);
+                destPath = AssetPathUtility.SanitizeAssetPath(destinationPath);
                 if (AssetExists(destPath))
                     return Response.Error($"Asset already exists at destination path: {destPath}");
                 // Ensure destination directory exists
@@ -576,8 +576,8 @@ namespace MCPForUnity.Editor.Tools
             if (string.IsNullOrEmpty(destinationPath))
                 return Response.Error("'destination' path is required for move/rename.");
 
-            string sourcePath = SanitizeAssetPath(path);
+            string sourcePath = AssetPathUtility.SanitizeAssetPath(path);
-            string destPath = SanitizeAssetPath(destinationPath);
+            string destPath = AssetPathUtility.SanitizeAssetPath(destinationPath);
 
             if (!AssetExists(sourcePath))
                 return Response.Error($"Source asset not found at path: {sourcePath}");
@@ -642,7 +642,7 @@ namespace MCPForUnity.Editor.Tools
             string[] folderScope = null;
             if (!string.IsNullOrEmpty(pathScope))
             {
-                folderScope = new string[] { SanitizeAssetPath(pathScope) };
+                folderScope = new string[] { AssetPathUtility.SanitizeAssetPath(pathScope) };
                 if (!AssetDatabase.IsValidFolder(folderScope[0]))
                 {
                     // Maybe the user provided a file path instead of a folder?
@@ -732,7 +732,7 @@ namespace MCPForUnity.Editor.Tools
         {
             if (string.IsNullOrEmpty(path))
                 return Response.Error("'path' is required for get_info.");
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(fullPath))
                 return Response.Error($"Asset not found at path: {fullPath}");
 
@@ -761,7 +761,7 @@ namespace MCPForUnity.Editor.Tools
                 return Response.Error("'path' is required for get_components.");
 
             // 2. Sanitize and check existence
-            string fullPath = SanitizeAssetPath(path);
+            string fullPath = AssetPathUtility.SanitizeAssetPath(path);
             if (!AssetExists(fullPath))
                 return Response.Error($"Asset not found at path: {fullPath}");
 
@@ -829,18 +829,6 @@ namespace MCPForUnity.Editor.Tools
         /// <summary>
         /// Ensures the asset path starts with "Assets/".
         /// </summary>
-        private static string SanitizeAssetPath(string path)
-        {
-            if (string.IsNullOrEmpty(path))
-                return path;
-            path = path.Replace('\\', '/'); // Normalize separators
-            if (!path.StartsWith("Assets/", StringComparison.OrdinalIgnoreCase))
-            {
-                return "Assets/" + path.TrimStart('/');
-            }
-            return path;
-        }
-
         /// <summary>
         /// Checks if an asset exists at the given path (file or folder).
         /// </summary>
@@ -930,10 +918,12 @@ namespace MCPForUnity.Editor.Tools
                         );
                     }
                 }
-            } else if (properties["color"] is JArray colorArr) //Use color now with examples set in manage_asset.py
+            }
+            else if (properties["color"] is JArray colorArr) //Use color now with examples set in manage_asset.py
             {
-                string propName =  "_Color"; 
+                string propName = "_Color";
-                try {
+                try
+                {
                     if (colorArr.Count >= 3)
                     {
                         Color newColor = new Color(
@@ -949,7 +939,8 @@ namespace MCPForUnity.Editor.Tools
                         }
                     }
                 }
-                catch (Exception ex) {
+                catch (Exception ex)
+                {
                     Debug.LogWarning(
                         $"Error parsing color property '{propName}': {ex.Message}"
                     );
@@ -989,7 +980,7 @@ namespace MCPForUnity.Editor.Tools
                 if (!string.IsNullOrEmpty(texPath))
                 {
                     Texture newTex = AssetDatabase.LoadAssetAtPath<Texture>(
-                        SanitizeAssetPath(texPath)
+                        AssetPathUtility.SanitizeAssetPath(texPath)
                     );
                     if (
                         newTex != null
@@ -1217,7 +1208,7 @@ namespace MCPForUnity.Editor.Tools
                     && token.Type == JTokenType.String
                 )
                 {
-                    string assetPath = SanitizeAssetPath(token.ToString());
+                    string assetPath = AssetPathUtility.SanitizeAssetPath(token.ToString());
                     UnityEngine.Object loadedAsset = AssetDatabase.LoadAssetAtPath(
                         assetPath,
                         targetType
@@ -1337,4 +1328,3 @@ namespace MCPForUnity.Editor.Tools
         }
     }
 }
-

UnityMcpBridge/Editor/Tools/ManageEditor.cs

@@ -5,8 +5,9 @@ using System.IO;
 using Newtonsoft.Json.Linq;
 using UnityEditor;
 using UnityEditorInternal; // Required for tag management
+using UnityEditor.SceneManagement;
 using UnityEngine;
-using MCPForUnity.Editor.Helpers; // For Response class
+using MCPForUnity.Editor.Helpers;
 
 namespace MCPForUnity.Editor.Tools
 {
@@ -98,6 +99,8 @@ namespace MCPForUnity.Editor.Tools
                     return GetActiveTool();
                 case "get_selection":
                     return GetSelection();
+                case "get_prefab_stage":
+                    return GetPrefabStageInfo();
                 case "set_active_tool":
                     string toolName = @params["toolName"]?.ToString();
                     if (string.IsNullOrEmpty(toolName))
@@ -140,7 +143,7 @@ namespace MCPForUnity.Editor.Tools
 
                 default:
                     return Response.Error(
-                        $"Unknown action: '{action}'. Supported actions include play, pause, stop, get_state, get_project_root, get_windows, get_active_tool, get_selection, set_active_tool, add_tag, remove_tag, get_tags, add_layer, remove_layer, get_layers."
+                        $"Unknown action: '{action}'. Supported actions include play, pause, stop, get_state, get_project_root, get_windows, get_active_tool, get_selection, get_prefab_stage, set_active_tool, add_tag, remove_tag, get_tags, add_layer, remove_layer, get_layers."
                     );
             }
         }
@@ -244,6 +247,35 @@ namespace MCPForUnity.Editor.Tools
             }
         }
 
+        private static object GetPrefabStageInfo()
+        {
+            try
+            {
+                PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+                if (stage == null)
+                {
+                    return Response.Success
+                    ("No prefab stage is currently open.", new { isOpen = false });
+                }
+
+                return Response.Success(
+                    "Prefab stage info retrieved.",
+                    new
+                    {
+                        isOpen = true,
+                        assetPath = stage.assetPath,
+                        prefabRootName = stage.prefabContentsRoot != null ? stage.prefabContentsRoot.name : null,
+                        mode = stage.mode.ToString(),
+                        isDirty = stage.scene.isDirty
+                    }
+                );
+            }
+            catch (Exception e)
+            {
+                return Response.Error($"Error getting prefab stage info: {e.Message}");
+            }
+        }
+
         private static object GetActiveTool()
         {
             try
@@ -610,4 +642,3 @@ namespace MCPForUnity.Editor.Tools
         }
     }
 }
-

UnityMcpBridge/Editor/Tools/MenuItems/ManageMenuItem.cs

@@ -1,15 +1,9 @@
 using System;
 using Newtonsoft.Json.Linq;
-using UnityEditor;
-using UnityEngine;
 using MCPForUnity.Editor.Helpers;
 
 namespace MCPForUnity.Editor.Tools.MenuItems
 {
-    /// <summary>
-    /// Facade handler for managing Unity Editor menu items.
-    /// Routes actions to read or execute implementations.
-    /// </summary>
     public static class ManageMenuItem
     {
         /// <summary>

UnityMcpBridge/Editor/Tools/MenuItems/MenuItemExecutor.cs

@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using Newtonsoft.Json.Linq;
 using UnityEditor;
-using UnityEngine;
 using MCPForUnity.Editor.Helpers;
 
 namespace MCPForUnity.Editor.Tools.MenuItems
@@ -37,23 +36,12 @@ namespace MCPForUnity.Editor.Tools.MenuItems
 
             try
             {
-                // Execute on main thread using delayCall
+                bool executed = EditorApplication.ExecuteMenuItem(menuPath);
-                EditorApplication.delayCall += () =>
+                if (!executed)
                 {
-                    try
+                    McpLog.Error($"[MenuItemExecutor] Failed to execute menu item '{menuPath}'. It might be invalid, disabled, or context-dependent.");
-                    {
+                    return Response.Error($"Failed to execute menu item '{menuPath}'. It might be invalid, disabled, or context-dependent.");
-                        bool executed = EditorApplication.ExecuteMenuItem(menuPath);
+                }
-                        if (!executed)
-                        {
-                            McpLog.Error($"[MenuItemExecutor] Failed to execute menu item via delayCall: '{menuPath}'. It might be invalid, disabled, or context-dependent.");
-                        }
-                    }
-                    catch (Exception delayEx)
-                    {
-                        McpLog.Error($"[MenuItemExecutor] Exception during delayed execution of '{menuPath}': {delayEx}");
-                    }
-                };
-
                 return Response.Success($"Attempted to execute menu item: '{menuPath}'. Check Unity logs for confirmation or errors.");
             }
             catch (Exception e)

UnityMcpBridge/Editor/Tools/MenuItems/MenuItemsReader.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Linq;
 using Newtonsoft.Json.Linq;
 using UnityEditor;
-using UnityEngine;
 using MCPForUnity.Editor.Helpers;
 
 namespace MCPForUnity.Editor.Tools.MenuItems

UnityMcpBridge/Editor/Tools/Prefabs.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 1bd48a1b7555c46bba168078ce0291cc
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

UnityMcpBridge/Editor/Tools/Prefabs/ManagePrefabs.cs

@@ -0,0 +1,274 @@
+using System;
+using System.IO;
+using MCPForUnity.Editor.Helpers;
+using Newtonsoft.Json.Linq;
+using UnityEditor;
+using UnityEditor.SceneManagement;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+
+namespace MCPForUnity.Editor.Tools.Prefabs
+{
+    public static class ManagePrefabs
+    {
+        private const string SupportedActions = "open_stage, close_stage, save_open_stage, create_from_gameobject";
+
+        public static object HandleCommand(JObject @params)
+        {
+            if (@params == null)
+            {
+                return Response.Error("Parameters cannot be null.");
+            }
+
+            string action = @params["action"]?.ToString()?.ToLowerInvariant();
+            if (string.IsNullOrEmpty(action))
+            {
+                return Response.Error($"Action parameter is required. Valid actions are: {SupportedActions}.");
+            }
+
+            try
+            {
+                switch (action)
+                {
+                    case "open_stage":
+                        return OpenStage(@params);
+                    case "close_stage":
+                        return CloseStage(@params);
+                    case "save_open_stage":
+                        return SaveOpenStage();
+                    case "create_from_gameobject":
+                        return CreatePrefabFromGameObject(@params);
+                    default:
+                        return Response.Error($"Unknown action: '{action}'. Valid actions are: {SupportedActions}.");
+                }
+            }
+            catch (Exception e)
+            {
+                McpLog.Error($"[ManagePrefabs] Action '{action}' failed: {e}");
+                return Response.Error($"Internal error: {e.Message}");
+            }
+        }
+
+        private static object OpenStage(JObject @params)
+        {
+            string prefabPath = @params["prefabPath"]?.ToString();
+            if (string.IsNullOrEmpty(prefabPath))
+            {
+                return Response.Error("'prefabPath' parameter is required for open_stage.");
+            }
+
+            string sanitizedPath = AssetPathUtility.SanitizeAssetPath(prefabPath);
+            GameObject prefabAsset = AssetDatabase.LoadAssetAtPath<GameObject>(sanitizedPath);
+            if (prefabAsset == null)
+            {
+                return Response.Error($"No prefab asset found at path '{sanitizedPath}'.");
+            }
+
+            string modeValue = @params["mode"]?.ToString();
+            if (!string.IsNullOrEmpty(modeValue) && !modeValue.Equals(PrefabStage.Mode.InIsolation.ToString(), StringComparison.OrdinalIgnoreCase))
+            {
+                return Response.Error("Only PrefabStage mode 'InIsolation' is supported at this time.");
+            }
+
+            PrefabStage stage = PrefabStageUtility.OpenPrefab(sanitizedPath);
+            if (stage == null)
+            {
+                return Response.Error($"Failed to open prefab stage for '{sanitizedPath}'.");
+            }
+
+            return Response.Success($"Opened prefab stage for '{sanitizedPath}'.", SerializeStage(stage));
+        }
+
+        private static object CloseStage(JObject @params)
+        {
+            PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+            if (stage == null)
+            {
+                return Response.Success("No prefab stage was open.");
+            }
+
+            bool saveBeforeClose = @params["saveBeforeClose"]?.ToObject<bool>() ?? false;
+            if (saveBeforeClose && stage.scene.isDirty)
+            {
+                SaveStagePrefab(stage);
+                AssetDatabase.SaveAssets();
+            }
+
+            StageUtility.GoToMainStage();
+            return Response.Success($"Closed prefab stage for '{stage.assetPath}'.");
+        }
+
+        private static object SaveOpenStage()
+        {
+            PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+            if (stage == null)
+            {
+                return Response.Error("No prefab stage is currently open.");
+            }
+
+            SaveStagePrefab(stage);
+            AssetDatabase.SaveAssets();
+            return Response.Success($"Saved prefab stage for '{stage.assetPath}'.", SerializeStage(stage));
+        }
+
+        private static void SaveStagePrefab(PrefabStage stage)
+        {
+            if (stage?.prefabContentsRoot == null)
+            {
+                throw new InvalidOperationException("Cannot save prefab stage without a prefab root.");
+            }
+
+            bool saved = PrefabUtility.SaveAsPrefabAsset(stage.prefabContentsRoot, stage.assetPath);
+            if (!saved)
+            {
+                throw new InvalidOperationException($"Failed to save prefab asset at '{stage.assetPath}'.");
+            }
+        }
+
+        private static object CreatePrefabFromGameObject(JObject @params)
+        {
+            string targetName = @params["target"]?.ToString() ?? @params["name"]?.ToString();
+            if (string.IsNullOrEmpty(targetName))
+            {
+                return Response.Error("'target' parameter is required for create_from_gameobject.");
+            }
+
+            bool includeInactive = @params["searchInactive"]?.ToObject<bool>() ?? false;
+            GameObject sourceObject = FindSceneObjectByName(targetName, includeInactive);
+            if (sourceObject == null)
+            {
+                return Response.Error($"GameObject '{targetName}' not found in the active scene.");
+            }
+
+            if (PrefabUtility.IsPartOfPrefabAsset(sourceObject))
+            {
+                return Response.Error(
+                    $"GameObject '{sourceObject.name}' is part of a prefab asset. Open the prefab stage to save changes instead."
+                );
+            }
+
+            PrefabInstanceStatus status = PrefabUtility.GetPrefabInstanceStatus(sourceObject);
+            if (status != PrefabInstanceStatus.NotAPrefab)
+            {
+                return Response.Error(
+                    $"GameObject '{sourceObject.name}' is already linked to an existing prefab instance."
+                );
+            }
+
+            string requestedPath = @params["prefabPath"]?.ToString();
+            if (string.IsNullOrWhiteSpace(requestedPath))
+            {
+                return Response.Error("'prefabPath' parameter is required for create_from_gameobject.");
+            }
+
+            string sanitizedPath = AssetPathUtility.SanitizeAssetPath(requestedPath);
+            if (!sanitizedPath.EndsWith(".prefab", StringComparison.OrdinalIgnoreCase))
+            {
+                sanitizedPath += ".prefab";
+            }
+
+            bool allowOverwrite = @params["allowOverwrite"]?.ToObject<bool>() ?? false;
+            string finalPath = sanitizedPath;
+
+            if (!allowOverwrite && AssetDatabase.LoadAssetAtPath<UnityEngine.Object>(finalPath) != null)
+            {
+                finalPath = AssetDatabase.GenerateUniqueAssetPath(finalPath);
+            }
+
+            EnsureAssetDirectoryExists(finalPath);
+
+            try
+            {
+                GameObject connectedInstance = PrefabUtility.SaveAsPrefabAssetAndConnect(
+                    sourceObject,
+                    finalPath,
+                    InteractionMode.AutomatedAction
+                );
+
+                if (connectedInstance == null)
+                {
+                    return Response.Error($"Failed to save prefab asset at '{finalPath}'.");
+                }
+
+                Selection.activeGameObject = connectedInstance;
+
+                return Response.Success(
+                    $"Prefab created at '{finalPath}' and instance linked.",
+                    new
+                    {
+                        prefabPath = finalPath,
+                        instanceId = connectedInstance.GetInstanceID()
+                    }
+                );
+            }
+            catch (Exception e)
+            {
+                return Response.Error($"Error saving prefab asset at '{finalPath}': {e.Message}");
+            }
+        }
+
+        private static void EnsureAssetDirectoryExists(string assetPath)
+        {
+            string directory = Path.GetDirectoryName(assetPath);
+            if (string.IsNullOrEmpty(directory))
+            {
+                return;
+            }
+
+            string fullDirectory = Path.Combine(Directory.GetCurrentDirectory(), directory);
+            if (!Directory.Exists(fullDirectory))
+            {
+                Directory.CreateDirectory(fullDirectory);
+                AssetDatabase.Refresh();
+            }
+        }
+
+        private static GameObject FindSceneObjectByName(string name, bool includeInactive)
+        {
+            PrefabStage stage = PrefabStageUtility.GetCurrentPrefabStage();
+            if (stage?.prefabContentsRoot != null)
+            {
+                foreach (Transform transform in stage.prefabContentsRoot.GetComponentsInChildren<Transform>(includeInactive))
+                {
+                    if (transform.name == name)
+                    {
+                        return transform.gameObject;
+                    }
+                }
+            }
+
+            Scene activeScene = SceneManager.GetActiveScene();
+            foreach (GameObject root in activeScene.GetRootGameObjects())
+            {
+                foreach (Transform transform in root.GetComponentsInChildren<Transform>(includeInactive))
+                {
+                    GameObject candidate = transform.gameObject;
+                    if (candidate.name == name)
+                    {
+                        return candidate;
+                    }
+                }
+            }
+
+            return null;
+        }
+
+        private static object SerializeStage(PrefabStage stage)
+        {
+            if (stage == null)
+            {
+                return new { isOpen = false };
+            }
+
+            return new
+            {
+                isOpen = true,
+                assetPath = stage.assetPath,
+                prefabRootName = stage.prefabContentsRoot != null ? stage.prefabContentsRoot.name : null,
+                mode = stage.mode.ToString(),
+                isDirty = stage.scene.isDirty
+            };
+        }
+
+    }
+}

UnityMcpBridge/Editor/Tools/Prefabs/ManagePrefabs.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: c14e76b2aa7bb4570a88903b061e946e
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

UnityMcpBridge/UnityMcpServer~/src/tools/__init__.py

@@ -5,6 +5,7 @@ from .manage_scene import register_manage_scene_tools
 from .manage_editor import register_manage_editor_tools
 from .manage_gameobject import register_manage_gameobject_tools
 from .manage_asset import register_manage_asset_tools
+from .manage_prefabs import register_manage_prefabs_tools
 from .manage_shader import register_manage_shader_tools
 from .read_console import register_read_console_tools
 from .manage_menu_item import register_manage_menu_item_tools
@@ -22,6 +23,7 @@ def register_all_tools(mcp):
     register_manage_editor_tools(mcp)
     register_manage_gameobject_tools(mcp)
     register_manage_asset_tools(mcp)
+    register_manage_prefabs_tools(mcp)
     register_manage_shader_tools(mcp)
     register_read_console_tools(mcp)
     register_manage_menu_item_tools(mcp)

UnityMcpBridge/UnityMcpServer~/src/tools/manage_menu_item.py

@@ -13,7 +13,7 @@ from unity_connection import get_unity_connection, async_send_command_with_retry
 def register_manage_menu_item_tools(mcp: FastMCP):
     """Registers the manage_menu_item tool with the MCP server."""
 
-    @mcp.tool()
+    @mcp.tool(description="Manage Unity menu items (execute/list/exists). If you're not sure what menu item to use, use the 'list' action to find it before using 'execute'.")
     @telemetry_tool("manage_menu_item")
     async def manage_menu_item(
         ctx: Context,
@@ -25,18 +25,6 @@ def register_manage_menu_item_tools(mcp: FastMCP):
         refresh: Annotated[bool | None,
                            "Optional flag to force refresh of the menu cache when listing"] = None,
     ) -> dict[str, Any]:
-        """Manage Unity menu items (execute/list/exists).
-
-        Args:
-            ctx: The MCP context.
-            action: One of 'execute', 'list', 'exists'.
-            menu_path: Menu path for 'execute' or 'exists' (e.g., "File/Save Project").
-            search: Optional filter string for 'list'.
-            refresh: Optional flag to force refresh of the menu cache when listing.
-
-        Returns:
-            A dictionary with operation results ('success', 'data', 'error').
-        """
         # Prepare parameters for the C# handler
         params_dict: dict[str, Any] = {
             "action": action,

UnityMcpBridge/UnityMcpServer~/src/tools/manage_prefabs.py

@@ -0,0 +1,59 @@
+from typing import Annotated, Any, Literal
+from mcp.server.fastmcp import FastMCP, Context
+
+from telemetry_decorator import telemetry_tool
+from unity_connection import send_command_with_retry
+
+
+def register_manage_prefabs_tools(mcp: FastMCP) -> None:
+    """Register prefab management tools with the MCP server."""
+
+    @mcp.tool(description="Bridge for prefab management commands (stage control and creation).")
+    @telemetry_tool("manage_prefabs")
+    def manage_prefabs(
+        ctx: Context,
+        action: Annotated[Literal[
+            "open_stage",
+            "close_stage",
+            "save_open_stage",
+            "create_from_gameobject",
+        ], "One of open_stage, close_stage, save_open_stage, create_from_gameobject"],
+        prefab_path: Annotated[str | None,
+                               "Prefab asset path relative to Assets e.g. Assets/Prefabs/favorite.prefab"] = None,
+        mode: Annotated[str | None,
+                        "Optional prefab stage mode (only 'InIsolation' is currently supported)"] = None,
+        save_before_close: Annotated[bool | None,
+                                     "When true, `close_stage` will save the prefab before exiting the stage."] = None,
+        target: Annotated[str | None,
+                          "Scene GameObject name required for create_from_gameobject"] = None,
+        allow_overwrite: Annotated[bool | None,
+                                   "Allow replacing an existing prefab at the same path"] = None,
+        search_inactive: Annotated[bool | None,
+                                   "Include inactive objects when resolving the target name"] = None,
+    ) -> dict[str, Any]:
+        try:
+            params: dict[str, Any] = {"action": action}
+
+            if prefab_path:
+                params["prefabPath"] = prefab_path
+            if mode:
+                params["mode"] = mode
+            if save_before_close is not None:
+                params["saveBeforeClose"] = bool(save_before_close)
+            if target:
+                params["target"] = target
+            if allow_overwrite is not None:
+                params["allowOverwrite"] = bool(allow_overwrite)
+            if search_inactive is not None:
+                params["searchInactive"] = bool(search_inactive)
+            response = send_command_with_retry("manage_prefabs", params)
+
+            if isinstance(response, dict) and response.get("success"):
+                return {
+                    "success": True,
+                    "message": response.get("message", "Prefab operation successful."),
+                    "data": response.get("data"),
+                }
+            return response if isinstance(response, dict) else {"success": False, "message": str(response)}
+        except Exception as exc:
+            return {"success": False, "message": f"Python error managing prefabs: {exc}"}