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

Author: msanatan

UnityMcpBridge/Editor/MCPForUnityBridge.cs

@@ -15,6 +15,7 @@
 using MCPForUnity.Editor.Models;
 using MCPForUnity.Editor.Tools;
 using MCPForUnity.Editor.Tools.MenuItems;
+using MCPForUnity.Editor.Tools.Prefabs;
 
 namespace MCPForUnity.Editor
 {
@@ -1055,6 +1056,7 @@ private static string ExecuteCommand(Command command)
                     "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}"
                     ),

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

@@ -5,6 +5,7 @@
 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_prefabs.py

@@ -0,0 +1,62 @@
+from typing import 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()
+    @telemetry_tool("manage_prefabs")
+    def manage_prefabs(
+        ctx: Context,
+        action: Literal["open_stage", "close_stage", "save_open_stage", "apply_instance_overrides", "revert_instance_overrides"],
+        path: str | None = None,
+        mode: str | None = None,
+        save_before_close: bool | None = None,
+        instance_id: int | None = None,
+        target: str | None = None,
+    ) -> dict[str, Any]:
+        """Bridge for prefab management commands (stage control, instance overrides).
+
+        Args:
+            action: One of the supported prefab actions ("open_stage", "close_stage", "save_open_stage",
+                "apply_instance_overrides", "revert_instance_overrides").
+            path: Prefab asset path (used by "open_stage").
+            mode: Optional prefab stage mode (currently only "InIsolation" is supported by the C# side).
+            save_before_close: When true, `close_stage` will save the prefab before exiting the stage.
+            instance_id: Prefab instance ID for apply/revert overrides. Accepts int-like values.
+            target: Scene GameObject name/path to resolve prefab instance when `instance_id` isn't provided.
+        Returns:
+            Dictionary mirroring the Unity bridge response.
+        """
+        try:
+            params: dict[str, str] = {"action": action}
+
+            if path:
+                params["path"] = path
+            if mode:
+                params["mode"] = mode
+            if save_before_close is not None:
+                params["saveBeforeClose"] = bool(save_before_close)
+
+            coerced_instance_id = int(instance_id)
+            if coerced_instance_id is not None:
+                params["instanceId"] = coerced_instance_id
+
+            if target:
+                params["target"] = target
+
+            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}"}