# How to integrate Emaillistverify MCP with Mastra AI

```json
{
  "title": "How to integrate Emaillistverify MCP with Mastra AI",
  "toolkit": "Emaillistverify",
  "toolkit_slug": "emaillistverify",
  "framework": "Mastra AI",
  "framework_slug": "mastra-ai",
  "url": "https://composio.dev/toolkits/emaillistverify/framework/mastra-ai",
  "markdown_url": "https://composio.dev/toolkits/emaillistverify/framework/mastra-ai.md",
  "updated_at": "2026-05-12T10:10:14.160Z"
}
```

## Introduction

This guide walks you through connecting Emaillistverify to Mastra AI using the Composio tool router. By the end, you'll have a working Emaillistverify agent that can check if this email address is valid, get detailed deliverability info for an email, verify a user's email before signup through natural language commands.
This guide will help you understand how to give your Mastra AI agent real control over a Emaillistverify account through Composio's Emaillistverify MCP server.
Before we dive in, let's take a quick look at the key ideas and tools involved.

## Also integrate Emaillistverify with

- [OpenAI Agents SDK](https://composio.dev/toolkits/emaillistverify/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/emaillistverify/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/emaillistverify/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/emaillistverify/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/emaillistverify/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/emaillistverify/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/emaillistverify/framework/hermes-agent)
- [CLI](https://composio.dev/toolkits/emaillistverify/framework/cli)
- [Google ADK](https://composio.dev/toolkits/emaillistverify/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/emaillistverify/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/emaillistverify/framework/ai-sdk)
- [LlamaIndex](https://composio.dev/toolkits/emaillistverify/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/emaillistverify/framework/crew-ai)

## TL;DR

Here's what you'll learn:
- Set up your environment so Mastra, OpenAI, and Composio work together
- Create a Tool Router session in Composio that exposes Emaillistverify tools
- Connect Mastra's MCP client to the Composio generated MCP URL
- Fetch Emaillistverify tool definitions and attach them as a toolset
- Build a Mastra agent that can reason, call tools, and return structured results
- Run an interactive CLI where you can chat with your Emaillistverify agent

## What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.
Key features include:
- MCP Client: Built-in support for Model Context Protocol servers
- Toolsets: Organize tools into logical groups
- Step Callbacks: Monitor and debug agent execution
- OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

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

The Emaillistverify MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Emaillistverify account. It provides structured and secure access to your email verification tools, so your agent can validate addresses, check deliverability, and provide detailed insights into email list quality on your behalf.
- Real-time email verification: Instantly check if a single email address is valid and deliverable before adding it to your list or sending messages.
- Detailed email validation insights: Get in-depth reports on why an email address may be risky or undeliverable, including error types and validation reasons.
- Automated list hygiene: Quickly verify new signups or leads as they come in, helping you keep your email lists clean and up-to-date.
- Prevent bounced emails: Reduce hard bounces and protect your sender reputation by validating addresses before campaigns are sent.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `EMAILLISTVERIFY_CHECK_BLACKLISTS` | Check Blacklists | Tool to check an IP address (IPv4/IPv6) or domain against multiple DNS-based blacklists (DNSBLs) for spam or malicious activity. Use when you need to verify the reputation of an IP or domain. Rate limit: 10 requests/second. |
| `EMAILLISTVERIFY_CHECK_DISPOSABLE` | Check Disposable Domain | Tool to verify if an email domain is associated with temporary/disposable email addresses. Includes DNS record verification. Use when you need to validate if a domain is disposable before accepting email registrations. |
| `EMAILLISTVERIFY_DELETE_MAILLIST` | Delete Maillist | Tool to delete a finished email list. Use when you need to remove a completed verification list. Only lists that have completed verification can be deleted. |
| `EMAILLISTVERIFY_DOWNLOAD_MAILLIST` | Download Email List | Tool to download a finished email list with verification results. Supports customizable columns (firstName, lastName, gender, result, etc.) and file format (csv/xlsx). Rate limit: 5 requests/second. |
| `EMAILLISTVERIFY_FIND_CONTACT` | Find Contact Email | Tool to search for a contact's business email address by name and company domain. Returns possible emails with confidence levels (high/medium/low/unknown). Rate limit: 5 requests/second. Credits: 5 (with name) or 10 (domain only). |
| `EMAILLISTVERIFY_GET_API_FILE_INFO` | Get API File Info | Tool to retrieve progress of an uploaded email list verification. Returns status (errored/waiting/progress/finished) with download URLs when complete. |
| `EMAILLISTVERIFY_GET_CREDITS` | Get Credits | Tool to retrieve details about available on-demand and subscription credits. Use when you need to check credit balance before performing verifications. On-demand credits never expire, subscription credits are refreshed daily. Rate limit: 10 requests/second. |
| `EMAILLISTVERIFY_GET_EMAIL_JOB` | Get Email Job Status | Tool to get the status of an asynchronous email verification job. Use when you need to check if a verification job has completed and retrieve its results. Rate limit: 100 requests per second. |
| `EMAILLISTVERIFY_GET_MAILLIST_PROGRESS` | Get Maillist Progress | Tool to retrieve real-time progress updates for an uploaded email list verification. Shows status, completion percentage, and credit usage. Rate limit: 100 requests/second. |
| `EMAILLISTVERIFY_UPLOAD_EMAIL_LIST` | Upload Email List | Tool to upload an email list file for bulk verification. Accepts .csv, .txt, or .xlsx files (max 100MB, 1M rows). Returns an ID to query verification progress. Rate limit: 5 requests/second. |
| `EMAILLISTVERIFY_VERIFY_SINGLE_EMAIL` | Verify Single Email | Tool to verify email deliverability status of a single email address. Returns a plain text status representing deliverability. Rate limit: 10 requests/second. Credits required: 1. |
| `EMAILLISTVERIFY_VERIFY_SINGLE_EMAIL_DETAILED` | Verify Single Email Detailed | Tool to verify email deliverability with detailed metadata including MX server info, ESP, first/last name estimation, gender, and role detection. Use when you need comprehensive email validation beyond basic deliverability. Rate limit: 10 requests/second, requires 1 credit per verification. |

## Supported Triggers

None listed.

## Creating MCP Server - Stand-alone vs Composio SDK

The Emaillistverify MCP server is an implementation of the Model Context Protocol that connects your AI agent to Emaillistverify. It provides structured and secure access so your agent can perform Emaillistverify operations on your behalf through a secure, permission-based interface.
With Composio's managed implementation, you don't have to create your own developer app. For production, if you're building an end product, we recommend using your own credentials. The managed server helps you prototype fast and go from 0-1 faster.

## Step-by-step Guide

### 1. Prerequisites

Before starting, make sure you have:
- Node.js 18 or higher
- A Composio account with an active API key
- An OpenAI API key
- Basic familiarity with TypeScript

### 1. Getting API Keys for OpenAI and Composio

OpenAI API Key
- Go to the [OpenAI dashboard](https://platform.openai.com/settings/organization/api-keys) and create an API key.
- You need credits or a connected billing setup to use the models.
- Store the key somewhere safe.
Composio API Key
- Log in to the [Composio dashboard](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs).
- Go to Settings and copy your API key.
- This key lets your Mastra agent talk to Composio and reach Emaillistverify through MCP.

### 2. Install dependencies

Install the required packages.
What's happening:
- @composio/core is the Composio SDK for creating MCP sessions
- @mastra/core provides the Agent class
- @mastra/mcp is Mastra's MCP client
- @ai-sdk/openai is the model wrapper for OpenAI
- dotenv loads environment variables from .env
```bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv
```

### 3. Set up environment variables

Create a .env file in your project root.
What's happening:
- COMPOSIO_API_KEY authenticates your requests to Composio
- COMPOSIO_USER_ID tells Composio which user this session belongs to
- OPENAI_API_KEY lets the Mastra agent call OpenAI models
```bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key_here
```

### 4. Import libraries and validate environment

What's happening:
- dotenv/config auto loads your .env so process.env.* is available
- openai gives you a Mastra compatible model wrapper
- Agent is the Mastra agent that will call tools and produce answers
- MCPClient connects Mastra to your Composio MCP server
- Composio is used to create a Tool Router session
```typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

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

if (!openaiAPIKey) 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 as string,
});
```

### 5. Create a Tool Router session for Emaillistverify

What's happening:
- create spins up a short-lived MCP HTTP endpoint for this user
- The toolkits array contains "emaillistverify" for Emaillistverify access
- session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
```typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["emaillistverify"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Emaillistverify MCP URL:", composioMCPUrl);
```

### 6. Configure Mastra MCP client and fetch tools

What's happening:
- MCPClient takes an id for this client and a list of MCP servers
- The headers property includes the x-api-key for authentication
- getTools fetches the tool definitions exposed by the Emaillistverify toolkit
```typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
```

### 7. Create the Mastra agent

What's happening:
- Agent is the core Mastra agent
- name is just an identifier for logging and debugging
- instructions guide the agent to use tools instead of only answering in natural language
- model uses openai("gpt-5") to configure the underlying LLM
```typescript
const agent = new Agent({
    name: "emaillistverify-mastra-agent",
    instructions: "You are an AI agent with Emaillistverify tools via Composio.",
    model: "openai/gpt-5",
  });
```

### 8. Set up interactive chat interface

What's happening:
- messages keeps the full conversation history in Mastra's expected format
- agent.generate runs the agent with conversation history and Emaillistverify toolsets
- maxSteps limits how many tool calls the agent can take in a single run
- onStepFinish is a hook that prints intermediate steps for debugging
```typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\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({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        emaillistverify: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

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

## Complete Code

```typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

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

if (!openaiAPIKey) 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 as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["emaillistverify"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      emaillistverify: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "emaillistverify-mastra-agent",
    instructions: "You are an AI agent with Emaillistverify tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

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

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { emaillistverify: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();
```

## Conclusion

You've built a Mastra AI agent that can interact with Emaillistverify through Composio's Tool Router.
You can extend this further by:
- Adding other toolkits like Gmail, Slack, or GitHub
- Building a web-based chat interface around this agent
- Using multiple MCP endpoints to enable cross-app workflows

## How to build Emaillistverify MCP Agent with another framework

- [OpenAI Agents SDK](https://composio.dev/toolkits/emaillistverify/framework/open-ai-agents-sdk)
- [Claude Agent SDK](https://composio.dev/toolkits/emaillistverify/framework/claude-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/emaillistverify/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/emaillistverify/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/emaillistverify/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/emaillistverify/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/emaillistverify/framework/hermes-agent)
- [CLI](https://composio.dev/toolkits/emaillistverify/framework/cli)
- [Google ADK](https://composio.dev/toolkits/emaillistverify/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/emaillistverify/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/emaillistverify/framework/ai-sdk)
- [LlamaIndex](https://composio.dev/toolkits/emaillistverify/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/emaillistverify/framework/crew-ai)

## Related Toolkits

- [Reddit](https://composio.dev/toolkits/reddit) - Reddit is a social news platform with thriving user-driven communities (subreddits). It's the go-to place for discussion, content sharing, and viral marketing.
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- [Ahrefs](https://composio.dev/toolkits/ahrefs) - Ahrefs is an SEO and marketing platform for site audits, keyword research, and competitor insights. It helps you improve search rankings and drive organic traffic.
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- [Benchmark email](https://composio.dev/toolkits/benchmark_email) - Benchmark Email is a platform for creating, sending, and tracking email campaigns. It's built to help you engage audiences and analyze results—all in one place.
- [Bigmailer](https://composio.dev/toolkits/bigmailer) - BigMailer is an email marketing platform for managing multiple brands with white-labeling and automation. It helps teams streamline campaigns and simplify integration with Amazon SES.
- [Brandfetch](https://composio.dev/toolkits/brandfetch) - Brandfetch is an API that delivers company logos, colors, and visual branding assets. It helps marketers and developers keep brand visuals consistent everywhere.
- [Brevo](https://composio.dev/toolkits/brevo) - Brevo is an all-in-one email and SMS marketing platform for transactional messaging, automation, and CRM. It helps businesses engage customers and streamline communications through powerful campaign tools.
- [Campayn](https://composio.dev/toolkits/campayn) - Campayn is an email marketing platform for creating, sending, and managing campaigns. It helps businesses engage contacts and grow audiences with easy-to-use tools.
- [Cardly](https://composio.dev/toolkits/cardly) - Cardly is a platform for creating and sending personalized direct mail to customers. It helps businesses break through the digital clutter by getting real engagement via physical mailboxes.
- [ClickSend](https://composio.dev/toolkits/clicksend) - ClickSend is a cloud-based SMS and email marketing platform for businesses. It streamlines communication by enabling quick message delivery and contact management.
- [Crustdata](https://composio.dev/toolkits/crustdata) - CrustData is an AI-powered data intelligence platform for real-time company and people data. It helps B2B sales teams, AI SDRs, and investors react to live business signals.
- [Curated](https://composio.dev/toolkits/curated) - Curated is a platform for collecting, curating, and publishing newsletters. It streamlines content aggregation and distribution for creators and teams.
- [Customerio](https://composio.dev/toolkits/customerio) - Customer.io is a customer engagement platform for targeted messaging across email, SMS, and push. Easily automate, segment, and track communications with your audience.
- [Cutt ly](https://composio.dev/toolkits/cutt_ly) - Cutt.ly is a URL shortening service for managing and analyzing links. Streamline your workflows with quick, trackable, and branded short URLs.
- [Demio](https://composio.dev/toolkits/demio) - Demio is webinar software built for marketers, offering both live and automated sessions with interactive features. It helps teams engage audiences and optimize lead generation through detailed analytics.

## Frequently Asked Questions

### What are the differences in Tool Router MCP and Emaillistverify MCP?

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

### Can I use Tool Router MCP with Mastra AI?

Yes, you can. Mastra AI 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 Emaillistverify tools.

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

Yes, absolutely. You can configure which Emaillistverify 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 Emaillistverify data and credentials are handled as safely as possible.

---
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