# How to integrate Mails so MCP with Claude Agent SDK

```json
{
  "title": "How to integrate Mails so MCP with Claude Agent SDK",
  "toolkit": "Mails so",
  "toolkit_slug": "mails_so",
  "framework": "Claude Agent SDK",
  "framework_slug": "claude-agents-sdk",
  "url": "https://composio.dev/toolkits/mails_so/framework/claude-agents-sdk",
  "markdown_url": "https://composio.dev/toolkits/mails_so/framework/claude-agents-sdk.md",
  "updated_at": "2026-05-12T10:18:21.496Z"
}
```

## Introduction

This guide walks you through connecting Mails so to the Claude Agent SDK using the Composio tool router. By the end, you'll have a working Mails so agent that can check if this email address is valid, validate a list of emails before campaign, download results for last batch validation job through natural language commands.
This guide will help you understand how to give your Claude Agent SDK agent real control over a Mails so account through Composio's Mails so MCP server.
Before we dive in, let's take a quick look at the key ideas and tools involved.

## Also integrate Mails so with

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

## TL;DR

Here's what you'll learn:
- Get and set up your Claude/Anthropic and Composio API keys
- Install the necessary dependencies
- Initialize Composio and create a Tool Router session for Mails so
- Configure an AI agent that can use Mails so as a tool
- Run a live chat session where you can ask the agent to perform Mails so operations

## What is Claude Agent SDK?

The Claude Agent SDK is Anthropic's official framework for building AI agents powered by Claude. It provides a streamlined interface for creating agents with MCP tool support and conversation management.
Key features include:
- Native MCP Support: Built-in support for Model Context Protocol servers
- Permission Modes: Control tool execution permissions
- Streaming Responses: Real-time response streaming for interactive applications
- Context Manager: Clean async context management for sessions

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

The Mails so MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mails so account. It provides structured and secure access to advanced email validation services, so your agent can perform actions like verifying single emails, running bulk checks, and retrieving validation results on your behalf.
- Single email validation: Instantly check if an individual email address is valid and safe to use before sending important messages.
- Bulk email validation: Submit large lists of email addresses for automated deliverability and quality checks, keeping your contact databases clean.
- Batch results retrieval: Effortlessly fetch detailed validation outcomes for previously submitted bulk jobs, so you can review and act on the results.
- Email list hygiene automation: Use the agent to regularly scan and validate contact lists, reducing bounce rates and improving sender reputation.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `MAILS_SO_RETRIEVE_BATCH_RESULTS` | Retrieve Batch Results | Tool to retrieve results of a bulk validation job. Use after submitting a batch and you have its ID. |
| `MAILS_SO_VALIDATE_BULK_EMAILS` | Validate Bulk Emails | Tool to validate multiple email addresses in bulk. Use when you need to confirm deliverability of a list of emails at once. |
| `MAILS_SO_VALIDATE_SINGLE_EMAIL` | Validate Single Email | Tool to validate a single email address. Use when you need to check deliverability and quality details before sending an email. |

## Supported Triggers

None listed.

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

The Mails so MCP server is an implementation of the Model Context Protocol that connects your AI agent to Mails so. It provides structured and secure access so your agent can perform Mails so 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:
- Composio API Key and Claude/Anthropic API Key
- Primary know-how of Claude Agents SDK
- A Mails so account
- Some knowledge of Python

### 1. Getting API Keys for Claude/Anthropic and Composio

Claude/Anthropic API Key
- Go to the [Anthropic Console](https://console.anthropic.com/settings/organization/api-keys) and create an API key. You'll need credits to use the models.
- Keep the API key safe.
Composio API Key
- Log in to the [Composio dashboard](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs).
- Navigate to your API settings and generate a new API key.
- Store this key securely as you'll need it for authentication.

### 2. Install dependencies

No description provided.
```python
pip install composio-anthropic claude-agent-sdk python-dotenv
```

```typescript
npm install @anthropic-ai/claude-agent-sdk @composio/core dotenv
```

### 3. Set up environment variables

Create a .env file in your project root.
What's happening:
- COMPOSIO_API_KEY authenticates with Composio
- USER_ID identifies the user for session management
- ANTHROPIC_API_KEY authenticates with Anthropic/Claude
```bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
ANTHROPIC_API_KEY=your_anthropic_api_key_here
```

### 4. Import dependencies

No description provided.
```python
import asyncio
from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions
import os
from composio import Composio
from dotenv import load_dotenv

load_dotenv()
```

```typescript
import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

dotenv.config();
```

### 5. Create a Composio instance and Tool Router session

No description provided.
```python
async def chat_with_remote_mcp():
    api_key = os.getenv("COMPOSIO_API_KEY")
    if not api_key:
        raise RuntimeError("COMPOSIO_API_KEY is not set")

    composio = Composio(api_key=api_key)

    # Create Tool Router session for Mails so
    mcp_server = composio.create(
        user_id=os.getenv("USER_ID"),
        toolkits=["mails_so"]
    )

    url = mcp_server.mcp.url

    if not url:
        raise ValueError("Session URL not found")
```

```typescript
async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

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

  // Create Tool Router session for Mails so
  const session = await composio.create(USER_ID, {
    toolkits: ['mails_so'],
  });
  const mcpUrl = session?.mcp.url;
```

### 6. Configure Claude Agent with MCP

No description provided.
```python
# Configure remote MCP server for Claude
options = ClaudeAgentOptions(
    permission_mode="bypassPermissions",
    mcp_servers={
        "composio": {
            "type": "http",
            "url": url,
            "headers": {
                "x-api-key": os.getenv("COMPOSIO_API_KEY")
            }
        }
    },
    system_prompt="You are a helpful assistant with access to Mails so tools via Composio.",
    max_turns=10
)
```

```typescript
const options: Options = {
  permissionMode: 'bypassPermissions',
  mcpServers: {
    composio: {
      type: 'http',
      url: mcpUrl,
      headers: { 'x-api-key': COMPOSIO_API_KEY }
    }
  },
  systemPrompt: 'You are a helpful assistant with access to Mails so tools via Composio.',
  maxTurns: 10,
};
```

### 7. Create client and start chat loop

No description provided.
```python
# Create client with context manager
async with ClaudeSDKClient(options=options) as client:
    print("\nChat started. Type 'exit' or 'quit' to end.\n")

    # Main chat loop
    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit"}:
            print("Goodbye!")
            break

        # Send query
        await client.query(user_input)

        # Receive and print response
        print("Claude: ", end="", flush=True)
        async for message in client.receive_response():
            if hasattr(message, "content"):
                for block in message.content:
                    if hasattr(block, "text"):
                        print(block.text, end="", flush=True)
        print()
```

```typescript
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
  });

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}
```

### 8. Run the application

No description provided.
```python
if __name__ == "__main__":
    asyncio.run(chat_with_remote_mcp())
```

```typescript
try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}
```

## Complete Code

```python
import asyncio
from claude_agent_sdk import ClaudeSDKClient, ClaudeAgentOptions
import os
from composio import Composio
from dotenv import load_dotenv

load_dotenv()

async def chat_with_remote_mcp():
    api_key = os.getenv("COMPOSIO_API_KEY")
    if not api_key:
        raise RuntimeError("COMPOSIO_API_KEY is not set")

    composio = Composio(api_key=api_key)

    # Create Tool Router session for Mails so
    mcp_server = composio.create(
        user_id=os.getenv("USER_ID"),
        toolkits=["mails_so"]
    )

    url = mcp_server.mcp.url

    if not url:
        raise ValueError("Session URL not found")

    # Configure remote MCP server for Claude
    options = ClaudeAgentOptions(
        permission_mode="bypassPermissions",
        mcp_servers={
            "composio": {
                "type": "http",
                "url": url,
                "headers": {
                    "x-api-key": os.getenv("COMPOSIO_API_KEY")
                }
            }
        },
        system_prompt="You are a helpful assistant with access to Mails so tools via Composio.",
        max_turns=10
    )

    # Create client with context manager
    async with ClaudeSDKClient(options=options) as client:
        print("\nChat started. Type 'exit' or 'quit' to end.\n")

        # Main chat loop
        while True:
            user_input = input("You: ").strip()
            if user_input.lower() in {"exit", "quit"}:
                print("Goodbye!")
                break

            # Send query
            await client.query(user_input)

            # Receive and print response
            print("Claude: ", end="", flush=True)
            async for message in client.receive_response():
                if hasattr(message, "content"):
                    for block in message.content:
                        if hasattr(block, "text"):
                            print(block.text, end="", flush=True)
            print()

if __name__ == "__main__":
    asyncio.run(chat_with_remote_mcp())
```

```typescript
import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

  const composio = new Composio({ apiKey: COMPOSIO_API_KEY });
  const session = await composio.create(USER_ID, {
    toolkits: ['mails_so']
  });
  const mcp_url = session?.mcp.url;

  const options: Options = {
    permissionMode: 'bypassPermissions',
    mcpServers: {
      composio: {
        type: 'http',
        url: mcp_url,
        headers: { 'x-api-key': COMPOSIO_API_KEY }
      }
    },
    systemPrompt: 'You are a helpful assistant with access to Mails so tools via Composio.',
    maxTurns: 10,
  };

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

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}

try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}
```

## Conclusion

You've successfully built a Claude Agent SDK agent that can interact with Mails so through Composio's Tool Router.
Key features:
- Native MCP support through Claude's agent framework
- Streaming responses for real-time interaction
- Permission bypass for smooth automated workflows
You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.

## How to build Mails so MCP Agent with another framework

- [OpenAI Agents SDK](https://composio.dev/toolkits/mails_so/framework/open-ai-agents-sdk)
- [Claude Code](https://composio.dev/toolkits/mails_so/framework/claude-code)
- [Claude Cowork](https://composio.dev/toolkits/mails_so/framework/claude-cowork)
- [Codex](https://composio.dev/toolkits/mails_so/framework/codex)
- [OpenClaw](https://composio.dev/toolkits/mails_so/framework/openclaw)
- [Hermes](https://composio.dev/toolkits/mails_so/framework/hermes-agent)
- [CLI](https://composio.dev/toolkits/mails_so/framework/cli)
- [Google ADK](https://composio.dev/toolkits/mails_so/framework/google-adk)
- [LangChain](https://composio.dev/toolkits/mails_so/framework/langchain)
- [Vercel AI SDK](https://composio.dev/toolkits/mails_so/framework/ai-sdk)
- [Mastra AI](https://composio.dev/toolkits/mails_so/framework/mastra-ai)
- [LlamaIndex](https://composio.dev/toolkits/mails_so/framework/llama-index)
- [CrewAI](https://composio.dev/toolkits/mails_so/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.
- [Facebook](https://composio.dev/toolkits/facebook) - Facebook is a social media and advertising platform for businesses and creators. It helps you connect, share, and manage content across your public Facebook Pages.
- [Linkedin](https://composio.dev/toolkits/linkedin) - LinkedIn is a professional networking platform for connecting, sharing content, and engaging with business opportunities. It's the go-to place for building your professional brand and unlocking new career connections.
- [Active campaign](https://composio.dev/toolkits/active_campaign) - ActiveCampaign is a marketing automation and CRM platform for managing email campaigns, sales pipelines, and customer segmentation. It helps businesses engage customers and drive growth through smart automation and targeted outreach.
- [ActiveTrail](https://composio.dev/toolkits/active_trail) - ActiveTrail is a user-friendly email marketing and automation platform. It helps you reach subscribers and automate campaigns with ease.
- [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.
- [Amcards](https://composio.dev/toolkits/amcards) - AMCards lets you create and mail personalized greeting cards online. Build stronger customer relationships with easy, automated card campaigns.
- [Beamer](https://composio.dev/toolkits/beamer) - Beamer is a news and changelog platform for in-app announcements and feature updates. It helps companies boost user engagement by sharing news where users are most active.
- [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 Mails so MCP?

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

### Can I use Tool Router MCP with Claude Agent SDK?

Yes, you can. Claude Agent 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 Mails so tools.

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

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

---
[See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)