VfsBackend

Node.js VFS backend for deepagents.

Provides an in-memory virtual file system for agent operations, allowing agents to read/write files without affecting the real filesystem.

This implementation uses node-vfs-polyfill which implements the upcoming Node.js VFS feature. Files are stored entirely in-memory using the VFS.

Basic Usage

import { VfsBackend } from "@langchain/node-vfs";

// Create and initialize a VFS backend
const backend = await VfsBackend.create({
  initialFiles: {
    "/src/index.js": "console.log('Hello')",
  },
});

try {
  // Read files directly
  const result = await backend.read("/src/index.js");
  console.log(result.content);
} finally {
  await backend.stop();
}

Using with DeepAgent

import { createDeepAgent } from "deepagents";
import { VfsBackend } from "@langchain/node-vfs";

const backend = await VfsBackend.create();

const agent = createDeepAgent({
  model: new ChatAnthropic({ model: "claude-sonnet-4-20250514" }),
  systemPrompt: "You are a coding assistant with VFS access.",
  backend,
});