mcp-use - The fullstack MCP framework to develop MCP Apps for ChatGPT / Claude and MCP Servers for AI Agents.

MCP notifications are one-way JSON-RPC messages with no response. Register a handler when your application needs to react to server updates.

Receive server notifications

Set a default handler on the client:

import { MCPClient } from "@mcp-use/client";

const client = new MCPClient({
  mcpServers: {
    demo: { url: "http://localhost:3000/mcp" },
  },
  onNotification: async (notification) => {
    console.log(notification.method, notification.params);
  },
});

An individual server configuration can provide its own onNotification callback. Per-server callbacks take precedence over the global default. You can also register a handler on a connection:

const connection = await client.connect("demo");

connection.on("notification", async (notification) => {
  if (notification.method === "notifications/tools/list_changed") {
    await connection.listTools();
  }
});

The standard list-change method names are:

notifications/tools/list_changed
notifications/resources/list_changed
notifications/prompts/list_changed

The client automatically refreshes its tool cache for tool list changes. Refresh resources or prompts when your application needs their updated values.

React

Each server managed by McpClientProvider exposes:

notifications, the stored notification entries
unreadNotificationCount
markNotificationRead, markAllNotificationsRead, and clearNotifications

Set onNotificationReceived on a server configuration to run custom logic when the provider receives and stores a notification.

Roots compatibility

setRoots() and getRoots() are compatibility APIs for sessionful servers. Roots are not part of the current sessionless protocol. For a compatible server, pass initial roots in its client configuration:

import { MCPClient } from "@mcp-use/client";

const client = new MCPClient({
  mcpServers: {
    legacy: {
      url: "http://localhost:3000/mcp",
      roots: [{ uri: "file:///home/user/project", name: "Project" }],
    },
  },
});

Calling connection.setRoots(roots) replaces the cached roots and sends notifications/roots/list_changed when connected. connection.getRoots() returns the current cached list. Use these methods only for a server that negotiated the sessionful protocol and requests roots. Server-side notification sending is covered in Notifications.

Get Started

MCP Server

MCP Apps

MCP Client

MCP Agent

Tooling

Notifications

Receive server notifications

React

Roots compatibility

​Receive server notifications

​React

​Roots compatibility

​Related

Receive server notifications

React

Roots compatibility

Related