How to integrate Nextdns MCP with Vercel AI SDK

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Introduction

This guide walks you through connecting Nextdns to Vercel AI SDK using the Composio tool router. By the end, you'll have a working Nextdns agent that can block access to adult websites for a profile, download dns logs from last week, show top domains queried by my devices, clear all dns logs for my home profile through natural language commands.

This guide will help you understand how to give your Vercel AI SDK agent real control over a Nextdns account through Composio's Nextdns MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

TL;DR

Here's what you'll learn:
  • How to set up and configure a Vercel AI SDK agent with Nextdns integration
  • Using Composio's Tool Router to dynamically load and access Nextdns tools
  • Creating an MCP client connection using HTTP transport
  • Building an interactive CLI chat interface with conversation history management
  • Handling tool calls and results within the Vercel AI SDK framework

What is Vercel AI SDK?

The Vercel AI SDK is a TypeScript library for building AI-powered applications. It provides tools for creating agents that can use external services and maintain conversation state.

Key features include:

  • streamText: Core function for streaming responses with real-time tool support
  • MCP Client: Built-in support for Model Context Protocol
  • Step Counting: Control multi-step tool execution
  • OpenAI Provider: Native integration with OpenAI models

What is the Nextdns MCP server, and what's possible with it?

The Nextdns MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Nextdns account. It provides structured and secure access to your DNS security and privacy controls, so your agent can perform actions like blocking domains, managing profiles, analyzing DNS analytics, and clearing logs on your behalf.

  • Dynamic domain and TLD blocking: Instantly add domains or top-level domains to your denylist or security blocklist, helping you stay ahead of new threats.
  • Profile management and configuration: Create, update, or delete NextDNS configuration profiles to tailor DNS filtering and security settings for different users or devices.
  • Comprehensive DNS analytics: Retrieve detailed analytics by device, domain, or client IP to monitor DNS activity, spot anomalies, and optimize security policies.
  • Log management and export: Download DNS query logs for audit or troubleshooting, or clear logs entirely to maintain your privacy.
  • Control over block page settings: Enable or disable the block page for any configuration, giving you flexibility over how blocks are displayed to users.

Supported Tools & Triggers

Tools
Add Blocked TLDTool to add a top-level domain to the security blocklist for a nextdns profile.
Add Denylist DomainTool to add a domain to the denylist of a nextdns profile.
Toggle Block PageTool to enable or disable block page for a configuration.
Clear LogsTool to clear dns logs for a nextdns profile.
Create ProfileThis tool allows users to create a new nextdns profile.
Delete NextDNS ConfigurationTool to delete a nextdns configuration profile.
Download LogsTool to download dns logs for a profile.
Get Analytics DevicesTool to retrieve analytics aggregated by devices.
Get Analytics DomainsTool to retrieve analytics data for domains within a specific profile.
Get Analytics IPsTool to retrieve analytics aggregated by client ip addresses.
Get Analytics IP VersionsTool to retrieve analytics grouped by ip version within a specific profile.
Get Analytics Query TypesTool to retrieve dns query counts broken down by query type.
Get Analytics ReasonsTool to retrieve dns query counts broken down by classification reason.
Get Analytics StatusTool to retrieve analytics status for a specific profile.
Get LogsTool to retrieve logs for a specific nextdns profile with optional filters.
Get Profile DetailsRetrieves the details of a specific nextdns profile.
Get Setup InfoTool to get setup information for a provided configuration (profile).
List ConfigurationsTool to list all configurations (profiles) available on the nextdns account.
List Denylist DomainsTool to list domains in the denylist for a profile.
List Security SettingsTool to list current security options for a nextdns configuration.
List SettingsTool to list settings for a nextdns profile.
Log Client IPsTool to enable or disable logging of client ips for a nextdns configuration.
Toggle Domain LoggingTool to enable or disable logging of domains for a nextdns profile.
NextDNS LoginTool to authenticate to the nextdns api.
Get Monthly QueriesTool to get the number of dns queries made in the current month for a profile.
Remove Blocked TLDTool to remove a top-level domain from the security blocklist for a nextdns profile.
Remove Denylist DomainTool to remove a domain from a profile's denylist.
Rename ConfigurationTool to rename a nextdns configuration (profile).
Set AI Threat DetectionTool to enable or disable ai threat detection for a nextdns configuration.
Toggle Cryptojacking ProtectionTool to enable or disable cryptojacking protection for a nextdns configuration.
Set CSAM BlockingTool to enable or disable blocking of child sexual abuse material domains for a nextdns profile.
Toggle DGA ProtectionTool to enable or disable dga (domain generation algorithm) protection for a nextdns configuration.
Set DNS Rebinding ProtectionTool to enable or disable dns rebinding protection for a nextdns configuration.
Set Homograph ProtectionTool to enable or disable homograph attack protection for a nextdns configuration.
Set Newly Registered DomainsTool to enable or disable blocking of newly registered domains for a nextdns profile.
Toggle Parked Domains BlockingTool to enable or disable blocking of parked domains for a nextdns configuration.
Set Safe BrowsingTool to enable or disable google safe browsing for a nextdns configuration.
Toggle Threat Intelligence FeedsTool to enable or disable real-time threat intelligence feeds for a nextdns configuration.
Toggle Typosquatting ProtectionTool to enable or disable typosquatting protection for a nextdns configuration.
Update linked IPTool to update the linked ip for a nextdns profile.
Update Performance SettingsTool to update performance settings of a nextdns profile.
Update Privacy SettingsTool to update privacy settings for a profile.
Update ProfileTool to update an existing profile.

What is the Composio tool router, and how does it fit here?

What is Tool Router?

Composio's Tool Router helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Tool Router

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Tool Router works

The Tool Router follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Prerequisites

Before you begin, make sure you have:
  • Node.js and npm installed
  • A Composio account with API key
  • An OpenAI API key

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.

Install required dependencies

bash
npm install @ai-sdk/openai @ai-sdk/mcp @composio/core ai dotenv

First, install the necessary packages for your project.

What you're installing:

  • @ai-sdk/openai: Vercel AI SDK's OpenAI provider
  • @ai-sdk/mcp: MCP client for Vercel AI SDK
  • @composio/core: Composio SDK for tool integration
  • ai: Core Vercel AI SDK
  • dotenv: Environment variable management

Set up environment variables

bash
OPENAI_API_KEY=your_openai_api_key_here
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_user_id_here

Create a .env file in your project root.

What's needed:

  • OPENAI_API_KEY: Your OpenAI API key for GPT model access
  • COMPOSIO_API_KEY: Your Composio API key for tool access
  • COMPOSIO_USER_ID: A unique identifier for the user session

Import required modules and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Composio } from "@composio/core";
import * as readline from "readline";
import { streamText, type ModelMessage, stepCountIs } from "ai";
import { experimental_createMCPClient as createMCPClient } from "@ai-sdk/mcp";

const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!process.env.OPENAI_API_KEY) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey,
});
What's happening:
  • We're importing all necessary libraries including Vercel AI SDK's OpenAI provider and Composio
  • The dotenv/config import automatically loads environment variables
  • The MCP client import enables connection to Composio's tool server

Create Tool Router session and initialize MCP client

typescript
async function main() {
  // Create a tool router session for the user
  const { session } = await composio.create(composioUserID!, {
    toolkits: ["nextdns"],
  });

  const mcpUrl = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to Nextdns tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned mcp object contains the URL and authentication headers needed to connect to the MCP server
  • This session provides access to all Nextdns-related tools through the MCP protocol

Connect to MCP server and retrieve tools

typescript
const mcpClient = await createMCPClient({
  transport: {
    type: "http",
    url: mcpUrl,
    headers: session.mcp.headers, // Authentication headers for the Composio MCP server
  },
});

const tools = await mcpClient.tools();
What's happening:
  • We're creating an MCP client that connects to our Composio Tool Router session via HTTP
  • The mcp.url provides the endpoint, and mcp.headers contains authentication credentials
  • The type: "http" is important - Composio requires HTTP transport
  • tools() retrieves all available Nextdns tools that the agent can use

Initialize conversation and CLI interface

typescript
let messages: ModelMessage[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log(
  "Ask any questions related to nextdns, like summarize my last 5 emails, send an email, etc... :)))\n",
);

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: "> ",
});

rl.prompt();
What's happening:
  • We initialize an empty messages array to maintain conversation history
  • A readline interface is created to accept user input from the command line
  • Instructions are displayed to guide the user on how to interact with the agent

Handle user input and stream responses with real-time tool feedback

typescript
rl.on("line", async (userInput: string) => {
  const trimmedInput = userInput.trim();

  if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
    console.log("\nGoodbye!");
    rl.close();
    process.exit(0);
  }

  if (!trimmedInput) {
    rl.prompt();
    return;
  }

  messages.push({ role: "user", content: trimmedInput });
  console.log("\nAgent is thinking...\n");

  try {
    const stream = streamText({
      model: openai("gpt-5"),
      messages,
      tools,
      toolChoice: "auto",
      stopWhen: stepCountIs(10),
      onStepFinish: (step) => {
        for (const toolCall of step.toolCalls) {
          console.log(`[Using tool: ${toolCall.toolName}]`);
          }
          if (step.toolCalls.length > 0) {
            console.log(""); // Add space after tool calls
          }
        },
      });

      for await (const chunk of stream.textStream) {
        process.stdout.write(chunk);
      }

      console.log("\n\n---\n");

      // Get final result for message history
      const response = await stream.response;
      if (response?.messages?.length) {
        messages.push(...response.messages);
      }
    } catch (error) {
      console.error("\nAn error occurred while talking to the agent:");
      console.error(error);
      console.log(
        "\nYou can try again or restart the app if it keeps happening.\n",
      );
    } finally {
      rl.prompt();
    }
  });

  rl.on("close", async () => {
    await mcpClient.close();
    console.log("\nđź‘‹ Session ended.");
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • We use streamText instead of generateText to stream responses in real-time
  • toolChoice: "auto" allows the model to decide when to use Nextdns tools
  • stopWhen: stepCountIs(10) allows up to 10 steps for complex multi-tool operations
  • onStepFinish callback displays which tools are being used in real-time
  • We iterate through the text stream to create a typewriter effect as the agent responds
  • The complete response is added to conversation history to maintain context
  • Errors are caught and displayed with helpful retry suggestions

Complete Code

Here's the complete code to get you started with Nextdns and Vercel AI SDK:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Composio } from "@composio/core";
import * as readline from "readline";
import { streamText, type ModelMessage, stepCountIs } from "ai";
import { experimental_createMCPClient as createMCPClient } from "@ai-sdk/mcp";

const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!process.env.OPENAI_API_KEY) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey,
});

async function main() {
  // Create a tool router session for the user
  const { session } = await composio.create(composioUserID!, {
    toolkits: ["nextdns"],
  });

  const mcpUrl = session.mcp.url;

  const mcpClient = await createMCPClient({
    transport: {
      type: "http",
      url: mcpUrl,
      headers: session.mcp.headers, // Authentication headers for the Composio MCP server
    },
  });

  const tools = await mcpClient.tools();

  let messages: ModelMessage[] = [];

  console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
  console.log(
    "Ask any questions related to nextdns, like summarize my last 5 emails, send an email, etc... :)))\n",
  );

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: "> ",
  });

  rl.prompt();

  rl.on("line", async (userInput: string) => {
    const trimmedInput = userInput.trim();

    if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
      console.log("\nGoodbye!");
      rl.close();
      process.exit(0);
    }

    if (!trimmedInput) {
      rl.prompt();
      return;
    }

    messages.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    try {
      const stream = streamText({
        model: openai("gpt-5"),
        messages,
        tools,
        toolChoice: "auto",
        stopWhen: stepCountIs(10),
        onStepFinish: (step) => {
          for (const toolCall of step.toolCalls) {
            console.log(`[Using tool: ${toolCall.toolName}]`);
          }
          if (step.toolCalls.length > 0) {
            console.log(""); // Add space after tool calls
          }
        },
      });

      for await (const chunk of stream.textStream) {
        process.stdout.write(chunk);
      }

      console.log("\n\n---\n");

      // Get final result for message history
      const response = await stream.response;
      if (response?.messages?.length) {
        messages.push(...response.messages);
      }
    } catch (error) {
      console.error("\nAn error occurred while talking to the agent:");
      console.error(error);
      console.log(
        "\nYou can try again or restart the app if it keeps happening.\n",
      );
    } finally {
      rl.prompt();
    }
  });

  rl.on("close", async () => {
    await mcpClient.close();
    console.log("\nđź‘‹ Session ended.");
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});

Conclusion

You've successfully built a Nextdns agent using the Vercel AI SDK with streaming capabilities! This implementation provides a powerful foundation for building AI applications with natural language interfaces and real-time feedback.

Key features of this implementation:

  • Real-time streaming responses for a better user experience with typewriter effect
  • Live tool execution feedback showing which tools are being used as the agent works
  • Dynamic tool loading through Composio's Tool Router with secure authentication
  • Multi-step tool execution with configurable step limits (up to 10 steps)
  • Comprehensive error handling for robust agent execution
  • Conversation history maintenance for context-aware responses

You can extend this further by adding custom error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.

How to build Nextdns MCP Agent with another framework

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Claude Agent SDK

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LangChain

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Mastra AI

Mastra AI

Use Nextdns MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Nextdns MCP with LlamaIndex

CrewAI

CrewAI

Use Nextdns MCP with CrewAI

FAQ

What are the differences in Tool Router MCP and Nextdns MCP?

With a standalone Nextdns MCP server, the agents and LLMs can only access a fixed set of Nextdns tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Nextdns and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Vercel AI SDK?

Yes, you can. Vercel AI SDK fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Nextdns tools.

Can I manage the permissions and scopes for Nextdns while using Tool Router?

Yes, absolutely. You can configure which Nextdns scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Nextdns data and credentials are handled as safely as possible.

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