# How to integrate Realphonevalidation MCP with LangChain

```json
{
  "title": "How to integrate Realphonevalidation MCP with LangChain",
  "toolkit": "Realphonevalidation",
  "toolkit_slug": "realphonevalidation",
  "framework": "LangChain",
  "framework_slug": "langchain",
  "url": "https://composio.dev/toolkits/realphonevalidation/framework/langchain",
  "markdown_url": "https://composio.dev/toolkits/realphonevalidation/framework/langchain.md",
  "updated_at": "2026-05-12T10:23:28.074Z"
}
```

## Introduction

This guide walks you through connecting Realphonevalidation to LangChain using the Composio tool router. By the end, you'll have a working Realphonevalidation agent that can check if this phone number is active, validate if a number is wireless or landline, verify if this email address is disposable through natural language commands.
This guide will help you understand how to give your LangChain agent real control over a Realphonevalidation account through Composio's Realphonevalidation MCP server.
Before we dive in, let's take a quick look at the key ideas and tools involved.

## Also integrate Realphonevalidation with

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

## TL;DR

Here's what you'll learn:
- Get and set up your OpenAI and Composio API keys
- Connect your Realphonevalidation project to Composio
- Create a Tool Router MCP session for Realphonevalidation
- Initialize an MCP client and retrieve Realphonevalidation tools
- Build a LangChain agent that can interact with Realphonevalidation
- Set up an interactive chat interface for testing

## What is LangChain?

LangChain is a framework for developing applications powered by language models. It provides tools and abstractions for building agents that can reason, use tools, and maintain conversation context.
Key features include:
- Agent Framework: Build agents that can use tools and make decisions
- MCP Integration: Connect to external services through Model Context Protocol adapters
- Memory Management: Maintain conversation history across interactions
- Multi-Provider Support: Works with OpenAI, Anthropic, and other LLM providers

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

The Realphonevalidation MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Realphonevalidation account. It provides structured and secure access to advanced phone number and email verification services, so your agent can perform actions like real-time phone validation, carrier checks, bulk number scrubbing, and email deliverability checks on your behalf.
- Instant phone number validation: Let your agent verify if a phone number is active, its type (mobile or landline), carrier, and caller details in real time.
- Bulk number scrubbing: Automatically process and validate large lists of phone numbers, checking for connectivity and type to ensure data accuracy at scale.
- Email address verification: Have your agent check if an email is deliverable and not disposable, helping prevent bouncebacks and spam risks.
- Reassigned and consent compliance checks: Enable your agent to determine if a number has been reassigned since a specific consent date for regulatory compliance.
- Carrier and wireless identification: Easily identify whether a US phone number is wireless or landline for TCPA compliance and segmentation.

## Supported Tools

| Tool slug | Name | Description |
|---|---|---|
| `REALPHONEVALIDATION_CHECK_FRAUD` | Check Phone Fraud Risk | Tool to check phone number for fraud risk using Fraud Check API. Provides a phone risk score and many actionable data points including phone type, carrier, location, and recommendation (block, flag, allow). Use when you need to identify possible fraudulent phone numbers. US numbers only. |
| `REALPHONEVALIDATION_EMAIL_VERIFY` | Email Verification | Tool to validate an email address and check connectivity and disposability. Use after gathering an email to ensure it's deliverable and not disposable. |
| `REALPHONEVALIDATION_LOOKUP_DNC` | DNC Lookup | Tool to check Do Not Call list status for US phone numbers. Determines if number is on National, State, or DMA Do Not Call lists, identifies cell vs landline, and checks for known TCPA litigators. Requires SAN number from FTC. |
| `REALPHONEVALIDATION_RPV_ACTIVE` | Check Phone Active Status | Tool to determine if a phone number is active on a valid phone service provider. Use after collecting the user's phone number for real-time verification. |
| `REALPHONEVALIDATION_RPV_REASSIGNED_NUMBER_LOOKUP` | Reassigned Number Lookup | Tool to check if a phone number has been reassigned since a given consent date. Use when verifying number ownership status after obtaining user consent. |
| `REALPHONEVALIDATION_RPV_SCRUB_PLUS` | Scrub Plus Phone Numbers | Tool to scrub a phone number for connection status and type. Use to validate a US phone number's status and line type. |
| `REALPHONEVALIDATION_RPV_WIRELESS_ID` | Wireless ID | Tool to identify whether a US phone number is landline or wireless. Use when conducting TCPA compliance checks. |
| `REALPHONEVALIDATION_VALIDATE_PHONE_SCRUB` | Validate Phone Number (Scrub) | Tool to validate US phone numbers using budget-friendly Scrub API. Determines connectivity status quickly (under 2 seconds). Best for organizations with large lists/databases on tight budgets that only need connection status. Optional Iscell and Carrier fields available for additional charge. |
| `REALPHONEVALIDATION_VALIDATE_PHONE_TURBO_STANDARD` | Validate Phone Turbo Standard | Tool to perform real-time US phone validation using Turbo Standard API. Provides connection status and phone type (Mobile, Landline, VoIP). Optimized for web forms and apps when only connection status and phone type are needed. Faster than Turbo V3 when only basic validation is required. Returns results in about 2 seconds. |
| `REALPHONEVALIDATION_VALIDATE_PHONE_TURBO_V3` | Validate Phone Turbo V3 | Tool to perform comprehensive real-time phone validation using Turbo V3 API. Returns connection status, phone type (landline, cell, VoIP), carrier ID, caller name (when available), and caller type (consumer, business). Use when complete phone data overview is required in web forms. US numbers only. |

## Supported Triggers

None listed.

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

The Realphonevalidation MCP server is an implementation of the Model Context Protocol that connects your AI agent to Realphonevalidation. It provides structured and secure access so your agent can perform Realphonevalidation 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

No description provided.

### 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'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](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-langchain langchain-mcp-adapters langchain python-dotenv
```

```typescript
npm install @composio/langchain @langchain/core @langchain/openai @langchain/mcp-adapters 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's API
- COMPOSIO_USER_ID identifies the user for session management
- OPENAI_API_KEY enables access to OpenAI's language models
```bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_composio_user_id_here
OPENAI_API_KEY=your_openai_api_key_here
```

### 4. Import dependencies

No description provided.
```python
from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()
```

```typescript
import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

dotenv.config();
```

### 5. Initialize Composio client

What's happening:
- We're loading the COMPOSIO_API_KEY from environment variables and validating it exists
- Creating a Composio instance that will manage our connection to Realphonevalidation tools
- Validating that COMPOSIO_USER_ID is also set before proceeding
```python
async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))

    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
```

```typescript
const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });
```

### 6. Create a Tool Router session

What's happening:
- We're creating a Tool Router session that gives your agent access to Realphonevalidation tools
- The create method takes the user ID and specifies which toolkits should be available
- The returned session.mcp.url is the MCP server URL that your agent will use
- This approach allows the agent to dynamically load and use Realphonevalidation tools as needed
```python
# Create Tool Router session for Realphonevalidation
session = composio.create(
    user_id=os.getenv("COMPOSIO_USER_ID"),
    toolkits=['realphonevalidation']
)

url = session.mcp.url
```

```typescript
const session = await composio.create(
    userId as string,
    {
        toolkits: ['realphonevalidation']
    }
);

const url = session.mcp.url;
```

### 7. Configure the agent with the MCP URL

No description provided.
```python
client = MultiServerMCPClient({
    "realphonevalidation-agent": {
        "transport": "streamable_http",
        "url": session.mcp.url,
        "headers": {
            "x-api-key": os.getenv("COMPOSIO_API_KEY")
        }
    }
})

tools = await client.get_tools()

agent = create_agent("gpt-5", tools)
```

```typescript
const client = new MultiServerMCPClient({
    "realphonevalidation-agent": {
        transport: "http",
        url: url,
        headers: {
            "x-api-key": process.env.COMPOSIO_API_KEY
        }
    }
});

const tools = await client.getTools();

const agent = createAgent({ model: "gpt-5", tools });
```

### 8. Set up interactive chat interface

No description provided.
```python
conversation_history = []

print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
print("Ask any Realphonevalidation related question or task to the agent.\n")

while True:
    user_input = input("You: ").strip()

    if user_input.lower() in ['exit', 'quit', 'bye']:
        print("\nGoodbye!")
        break

    if not user_input:
        continue

    conversation_history.append({"role": "user", "content": user_input})
    print("\nAgent is thinking...\n")

    response = await agent.ainvoke({"messages": conversation_history})
    conversation_history = response['messages']
    final_response = response['messages'][-1].content
    print(f"Agent: {final_response}\n")
```

```typescript
let conversationHistory: any[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log("Ask any Realphonevalidation related question or task to the agent.\n");

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

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;
    }

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

    const response = await agent.invoke({ messages: conversationHistory });
    conversationHistory = response.messages;

    const finalResponse = response.messages[response.messages.length - 1]?.content;
    console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\n👋 Session ended.');
        process.exit(0);
    });
```

### 9. Run the application

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

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

## Complete Code

```python
from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
    
    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
    
    session = composio.create(
        user_id=os.getenv("COMPOSIO_USER_ID"),
        toolkits=['realphonevalidation']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "realphonevalidation-agent": {
            "transport": "streamable_http",
            "url": url,
            "headers": {
                "x-api-key": os.getenv("COMPOSIO_API_KEY")
            }
        }
    })
    
    tools = await client.get_tools()
  
    agent = create_agent("gpt-5", tools)
    
    conversation_history = []
    
    print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
    print("Ask any Realphonevalidation related question or task to the agent.\n")
    
    while True:
        user_input = input("You: ").strip()
        
        if user_input.lower() in ['exit', 'quit', 'bye']:
            print("\nGoodbye!")
            break
        
        if not user_input:
            continue
        
        conversation_history.append({"role": "user", "content": user_input})
        print("\nAgent is thinking...\n")
        
        response = await agent.ainvoke({"messages": conversation_history})
        conversation_history = response['messages']
        final_response = response['messages'][-1].content
        print(f"Agent: {final_response}\n")

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

```typescript
import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";  
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

    const session = await composio.create(
        userId as string,
        {
            toolkits: ['realphonevalidation']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "realphonevalidation-agent": {
            transport: "http",
            url: url,
            headers: {
                "x-api-key": process.env.COMPOSIO_API_KEY
            }
        }
    });
    
    const tools = await client.getTools();
  
    const agent = createAgent({ model: "gpt-5", tools });
    
    let conversationHistory: any[] = [];
    
    console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
    console.log("Ask any Realphonevalidation related question or task to the agent.\n");
    
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
        prompt: 'You: '
    });

    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;
        }
        
        conversationHistory.push({ role: "user", content: trimmedInput });
        console.log("\nAgent is thinking...\n");
        
        const response = await agent.invoke({ messages: conversationHistory });
        conversationHistory = response.messages;
        
        const finalResponse = response.messages[response.messages.length - 1]?.content;
        console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\nSession ended.');
        process.exit(0);
    });
}

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

## Conclusion

You've successfully built a LangChain agent that can interact with Realphonevalidation through Composio's Tool Router.
Key features of this implementation:
- Dynamic tool loading through Composio's Tool Router
- Conversation history maintenance for context-aware responses
- Async Python provides clean, efficient execution of agent workflows
You can extend this further by adding error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.

## How to build Realphonevalidation MCP Agent with another framework

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

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- [Beaconchain](https://composio.dev/toolkits/beaconchain) - Beaconchain is a real-time analytics platform for Ethereum 2.0's Beacon Chain. It provides detailed insights into validators, blocks, and overall network performance.
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## Frequently Asked Questions

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

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

### Can I use Tool Router MCP with LangChain?

Yes, you can. LangChain 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 Realphonevalidation tools.

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

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

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