unreal-mcp

Instructions

Implementation Reference

• server/editor/scripts/ue_get_asset_info.py:1-88 (handler)

  Core handler logic in Python script executed by Unreal Editor. Retrieves asset metadata including LOD levels for StaticMesh and SkeletalMesh using Unreal Python API.

  from typing import List, Dict, Any
  import unreal
  import json
  
  
  def get_asset_info(asset_path: str) -> List[Dict[str, Any]]:
      asset = unreal.EditorAssetLibrary.find_asset_data(asset_path)
      if asset.is_valid():
          asset_data = asset.get_asset()
          asset_info = {
              "name": asset_data.get_name(),
              "is_valid": asset.is_valid(),
              "is_u_asset": asset.is_u_asset(),
              "is_asset_loaded": asset.is_asset_loaded(),
              "class": asset_data.get_class().get_name(),
              "path": asset_data.get_path_name(),
              "package": asset_data.get_package().get_name(),
              "package_path": asset_data.get_package().get_path_name(),
          }
  
          # Add LOD information for assets that support it
          lod_info = get_lod_info(asset_data)
          if lod_info:
              asset_info["lod_levels"] = lod_info
  
          return [asset_info]
      else:
          return []
  
  
  def get_lod_info(asset_data) -> List[Dict[str, Any]]:
      lod_levels = []
  
      try:
          if isinstance(asset_data, unreal.StaticMesh):
              num_lods = asset_data.get_num_lods()
              for i in range(num_lods):
                  lod_data = asset_data.get_render_data().lod_resources[i]
                  lod_info = {
                      "lod_index": i,
                      "num_vertices": lod_data.get_num_vertices(),
                      "num_triangles": lod_data.get_num_triangles(),
                  }
                  lod_levels.append(lod_info)
  
          elif isinstance(asset_data, unreal.SkeletalMesh):
              editor_subsystem = unreal.get_editor_subsystem(
                  unreal.SkeletalMeshEditorSubsystem
              )
              if editor_subsystem:
                  try:
                      lod_count = editor_subsystem.get_lod_count(asset_data)
                      for lod_index in range(lod_count):
                          try:
                              lod_info_data = editor_subsystem.get_lod_info(
                                  asset_data, lod_index
                              )
                              lod_data = {
                                  "lod_index": lod_index,
                                  "lod_info": str(lod_info_data)
                                  if lod_info_data
                                  else None,
                              }
                              lod_levels.append(lod_data)
                          except Exception:
                              lod_data = {
                                  "lod_index": lod_index,
                                  "lod_info": None,
                              }
                              lod_levels.append(lod_data)
                  except Exception:
                      pass
  
      except Exception as e:
          # If we can't get LOD info, return empty list
          pass
  
      return lod_levels
  
  
  def main():
      asset_info = get_asset_info("${asset_path}")
      print(json.dumps(asset_info))
  
  
  if __name__ == "__main__":
      main()

• server/index.ts:193-208 (registration)

  Registers the 'editor_get_asset_info' tool in the MCP server, defines input schema { asset_path: z.string() }, and provides wrapper handler that executes the templated Python command.

  server.tool(
  	"editor_get_asset_info",
  	"Get information about an asset, including LOD levels for StaticMesh and SkeletalMesh assets\n\nExample output: [{'name': 'SM_Cube', 'is_valid': True, 'is_u_asset': True, 'is_asset_loaded': True, 'class': 'StaticMesh', 'path': '/Game/Meshes/SM_Cube', 'package': 'SM_Cube', 'package_path': '/Game/Meshes/SM_Cube', 'lod_levels': [{'lod_index': 0, 'num_vertices': 24, 'num_triangles': 12}, {'lod_index': 1, 'num_vertices': 16, 'num_triangles': 8}]}]\n\nReturns asset metadata with LOD information for mesh assets.",
  	{ asset_path: z.string() },
  	async ({ asset_path }) => {
  		const result = await tryRunCommand(editorTools.UEGetAssetInfo(asset_path))
  		return {
  			content: [
  				{
  					type: "text",
  					text: result,
  				},
  			],
  		}
  	},
  )

• server/editor/tools.ts:9-9 (helper)

  Helper function that reads the ue_get_asset_info.py script and applies Template with asset_path parameter to generate the Python code string for execution.

  export const UEGetAssetInfo = (asset_path: string) => Template(read("./scripts/ue_get_asset_info.py"), { asset_path })