createVfsBackendFactoryFromBackend

const backend = await VfsBackend.create();

const agent = createDeepAgent({
  model: new ChatAnthropic({ model: "claude-sonnet-4-20250514" }),
  systemPrompt: "You are a coding assistant.",
  middlewares: [
    createFilesystemMiddleware({
      backend: createVfsBackendFactoryFromBackend(backend),
    }),
  ],
});