Godot MCP

Instructions

Implementation Reference

• src/godot_mcp/godot.py:1387-1465 (handler)

  The implementation of `edit_primitive_mesh` method within `GodotController` which modifies the PrimitiveMesh resource of a MeshInstance3D.

  def edit_primitive_mesh(
      self,
      project_path: str,
      scene_path: str,
      node_path: str,
      mesh_type: str | None = None,
      mesh_parameters: dict[str, Any] | None = None,
      godot_executable: str | None = None,
  ) -> dict[str, Any]:
      project_dir = ensure_project_path(project_path)
      executable, version = resolve_godot_executable(godot_executable)
      absolute_scene_path, resource_scene_path = resolve_scene_path(project_dir, scene_path)
  
      if not absolute_scene_path.exists():
          raise GodotError(f"Scene not found: {absolute_scene_path}")
  
      normalized_node_path = normalize_scene_node_path(node_path)
      final_mesh_type = (mesh_type or "").strip()
      final_mesh_parameters = mesh_parameters or {}
      if not isinstance(final_mesh_parameters, dict):
          raise GodotError("`mesh_parameters` must be an object when provided.")
      if not final_mesh_type and not final_mesh_parameters:
          raise GodotError("Provide at least one of `mesh_type` or `mesh_parameters`.")
  
      payload: dict[str, Any] = {
          "mesh_parameters": final_mesh_parameters,
      }
      if final_mesh_type:
          payload["mesh_type"] = final_mesh_type
  
      try:
          with tempfile.NamedTemporaryFile(
              mode="w",
              encoding="utf-8",
              suffix="-godot-edit-primitive-mesh.json",
              delete=False,
          ) as handle:
              json.dump(payload, handle, ensure_ascii=False)
              config_path = handle.name
      except TypeError as exc:
          raise GodotError("`mesh_parameters` contains a value that could not be serialized to JSON.") from exc
  
      try:
          output = _run_godot_script(
              executable=executable,
              project_dir=project_dir,
              script_name="edit_primitive_mesh.gd",
              user_args=[
                  "--scene-path",
                  resource_scene_path,
                  "--node-path",
                  normalized_node_path,
                  "--config-path",
                  config_path,
              ],
          )
      finally:
          Path(config_path).unlink(missing_ok=True)
  
      parsed = _parse_script_json_output(output, "edit_primitive_mesh.gd")
      supported_mesh_parameters = parsed.get("supported_mesh_parameters", [])
      if not isinstance(supported_mesh_parameters, list):
          raise GodotError("Primitive mesh edit did not return a supported parameter list.")
  
      return {
          "project_path": str(project_dir),
          "scene_path": str(absolute_scene_path),
          "scene_resource_path": resource_scene_path,
          "node_path": parsed.get("node_path", normalized_node_path),
          "node_name": parsed.get("node_name"),
          "node_type": parsed.get("node_type", "MeshInstance3D"),
          "mesh_type_before": parsed.get("mesh_type_before"),
          "mesh_type_after": parsed.get("mesh_type_after"),
          "mesh_parameters": parsed.get("mesh_parameters", {}),
          "supported_mesh_parameters": supported_mesh_parameters,
          "updated_mesh_parameters": parsed.get("updated_mesh_parameters", []),
          "godot_executable": str(executable),
          "godot_version": version,
      }

• src/godot_mcp/server.py:601-642 (registration)

  The definition and registration of the `godot_edit_primitive_mesh` tool within the MCP server.

      name="godot_edit_primitive_mesh",
      description="Modify the PrimitiveMesh resource attached to an existing MeshInstance3D by changing its mesh type and/or one or more mesh parameters.",
      input_schema={
          "type": "object",
          "properties": {
              "project_path": {
                  "type": "string",
                  "description": "Path to the Godot project directory or its project.godot file.",
              },
              "scene_path": {
                  "type": "string",
                  "description": "Path to the target .tscn file. Absolute, relative, and res:// paths are supported.",
              },
              "node_path": {
                  "type": "string",
                  "description": "Scene-relative node path to the MeshInstance3D node that should be edited.",
              },
              "mesh_type": {
                  "type": "string",
                  "description": "Optional new PrimitiveMesh class such as BoxMesh, CylinderMesh, SphereMesh, CapsuleMesh, PlaneMesh, PrismMesh, QuadMesh, or TorusMesh.",
              },
              "mesh_parameters": {
                  "type": "object",
                  "description": "Primitive mesh property overrides such as size, radius, height, or segment counts.",
              },
              "godot_executable": {
                  "type": "string",
                  "description": "Optional explicit path to the Godot executable or .app bundle.",
              },
          },
          "required": ["project_path", "scene_path", "node_path"],
          "additionalProperties": False,
      },
      handler=lambda args: self.controller.edit_primitive_mesh(
          project_path=args["project_path"],
          scene_path=args["scene_path"],
          node_path=args["node_path"],
          mesh_type=args.get("mesh_type"),
          mesh_parameters=args.get("mesh_parameters"),
          godot_executable=args.get("godot_executable"),
      ),
  ),