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How To Connect Retell AI Voice Agent MCP Server To Your Favorite AI Assistant (like ChatGPT, Claude, etc.)
May 13, 2025
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The true power of modern AI assistants lies in their ability to connect with other specialized AI systems to extend their capabilities. While your existing AI can draft emails, analyze data, and generate content, what if it could seamlessly make actual AI phone calls? Retell has this covered with our proprietary MCP (Multichannel Communication Platform) Server integration.

By connecting your AI assistant to Retell AI's voice agent technology, you unlock a new dimension of business automation potential through the ability to initiate and conduct sophisticated AI phone calls, without human intervention, using your favorite AI assistants like ChatGPT, Claude, Grok, and many more. This integration represents the next evolution in AI capabilities: systems that can communicate across platforms and channels to deliver comprehensive and hyper efficient solutions.

This step-by-step guide will show you how to bridge the gap between your digital AI assistant and Retell's world of AI voice communication to create a powerful ecosystem of interconnected AI capabilities, especially cutting edge AI call automation.

See the reosurces necessary for establishing the MCP server connection instructions and code:
Retell MCP Server Package (NPM)
Retell MCP Server Repository (Github)

The Strategic Advantage of AI Voice Agents for Phone Calls

Before diving into the technical setup, let's explore why connecting your AI assistant to Retell AI's voice agents creates a powerful competitive advantage:

Unify Digital and Voice Channels for Seamless Customer Journeys: Retell AI's voice agents enable AI assistants to handle phone calls with human-like fluency, creating a cohesive experience across channels.

A 2023 study by Gartner found that 63% of customers prefer businesses offering consistent interactions across digital and voice platforms, boosting retention by up to 20%.

Convert Data Insights into Human Conversations: Retell AI's voice agents uses the very same advanced LLMs that power your AI assistant to engage in complex phone conversations. This allows your AI assistant to act on digital data, like customer preferences or purchase history, during calls.

Gather Rich Voice-Based Insights Automatically: By deploying Retell AI's voice agents, your AI assistant can conduct tasks with customers through automated phone calls to collect things like feedback, verify information, or schedule appointments.

A 2024 survey by Forrester revealed that businesses using AI-driven voice interactions reduced data collection costs by 30% compared to manual call centers, while capturing more accurate customer insights.

Turn Notifications into Interactive Dialogues: Retell AI's voice agents transform static notifications (e.g., appointment reminders) into dynamic, two-way personalized conversations, that enrich customer experience and enhance trust.

Enable Complex Decision-Making with Voice Data: Retell AI's integration empowers your AI assistant to analyze phone call outcomes and initiate sophisticated, multi-step processes. It can adjust things like schedules, update records, or escalate issues based on real-time voice interactions that ultimately streamline operations and enhance decision making.

Setting Up Retell AI MCP Server for Automated Phone Calls: A Clear, Step-by-Step Guide

Getting started with Retell AI's voice agent technology is straightforward, even for those without technical expertise. Follow these steps to integrate the MCP server with your AI assistant, here we are going to be basing it off connecting it to Claude:

Initial Setup

1. Open Claude -> Select "Settings" from the available options

2. Click on "Developer" in the settings menu

3. Select "Edit Config" to access your configuration settings

4. Open the JSON file using your preferred code editor

5. Visit the Retell AI MCP server NPM page and copy the configuration snippet

Retell AI MCP Server Code

6. Paste the configuration into your JSON file,

7. Generate a new Retell AI API token if you don't already have one

Retell AI API Key Generation Window

8. Replace the placeholder in your configuration with your newly generated API token

9. Save your configuration file

10. Restart Claude completely (quit and reopen the application) to register the new server

Important Note: When using the Retell AI MCP server for the first time, you may be prompted to grant permissions. You can choose to "Always Allow" for seamless future use.

After completing these steps, you'll be able to find the Retell AI MCP server in your tools list in Claude, confirming successful integration.

More of a visual learner? Watch our video tutorial on establishing a Retell MCP server connection!

Getting Started With Collaborating AI Assistants & AI Voice Agents

Once integrated, you can immediately start exploring the powerful capabilities of Retell AI's voice agent technology through Claude. Since it's fully integrated you can find out and act on any information in Retell AI through Claude, here's some examples:

  • Managing Your Phone Numbers: This gives you a complete inventory of available phone numbers for making AI-powered calls.
  • Exploring Your AI Voice Agents for Phone Calls: Examine the AI voice agents already configured in your account, and make calls directly through them.
  • Understanding Agent Capabilities: For deeper insight into specific agents, you can request detailed information about a particular agent (e.g., "Tell me more about the Pizzorra agent"), and review the comprehensive configuration information like voice technology used, agent conversation flow configuration, behavioral settings, and more.

Making Your First Automated AI Phone Call with Voice Agents

The true power of Retell AI lies in its ability to conduct human-like phone conversations. Here's how to initiate your first AI phone call:

  1. In Claude, select the agent you want to use from your available options
  2. Specify the phone number you wish to call
  3. Request Claude to initiate the call through the MCP server
  4. Monitor the call progress as it happens

During the call, your AI voice agent will:

  • Introduce itself using your configured identity
  • Follow its programmed conversational flow
  • Respond naturally to the recipient's questions and comments
  • Complete the intended task (ordering, scheduling, confirming, etc.)

Creating Custom AI Voice Agents for Automated Phone Calls in Seconds

Perhaps the most revolutionary aspect of Retell AI is the ability to create sophisticated voice agents from a single prompt. This capability dramatically reduces the technical barriers to implementing AI phone automation, letting you take charge of optimizing your call operations your way.  Here's how:

  1. Formulate a detailed prompt describing your desired agent, including:
    • The purpose of the call
    • Specific conversation elements to include
    • Agent personality and identity
    • Phone number to use
    • Preferred agent name
  2. Through AI assistant of choice submit this prompt to the MCP server
  3. Watch as the system automatically:
    • Creates the agent prompt
    • Configures the voice settings
    • Sets up the agent in your account
    • Prepares it for immediate calling
To further refine an AI voice agent for the most optimal and efficient telephony, LLMs, conversation pathways, etc. we highly recommend you use the Retell AI platform for best results.

Example Agent Creation Prompt

"Create an agent that calls my local pizza shop. Keep it brief. Order a margarita pizza and a Diet Coke. Payment cash on delivery. Address: 123 Main Street. Agent pretends to be me (John). Make an outbound call using USA number. Name the agent Pizza Orderer."

From this single instruction, the Retell AI MCP server handles the entire setup process without any additional configuration required, turning complex AI implementation into a simple conversation.

Additional AI Call Capabilities To Try

Reviewing Call Performance

After completing calls, you can analyze their performance:

  1. In Claude, request the call status from the MCP server
  2. Review key metrics including: start time, end time, call duration, and conversation summary

These insights help you refine your approach and understand the effectiveness of your automated communication strategy.

Maintaining Call Privacy

For security, compliance, or organizational purposes, you can easily manage your call records:

  1. Request deletion of specific calls when needed
  2. Confirm successful deletion to maintain appropriate and complianty record-keeping

Transform Your Business Operations with AI Voice Agent Phone Calls

Retell AI's voice agent technology opens up numerous practical applications for businesses looking to streamline operations:

Building the Next Generation of AI Phone Call Systems

The integration of Retell AI's MCP server with your existing AI assistant environment represents more than just a new feature, it's a fundamental shift in what's possible with enterprise AI voice agents. By connecting your digital AI capabilities to voice communication channels through Retell AI, you're building an interconnected AI ecosystem where:

  • Your AI assistant becomes multi-modal, capable of both digital interactions and AI phone calls
  • Information flows seamlessly between text-based analysis and voice agent conversations
  • Complex business processes can be fully automated from initial digital analysis to final voice agent confirmation calls
  • Business intelligence gathered through AI phone calls can inform your AI assistant's future recommendations
  • Your enterprise technology stack becomes truly integrated across all communication channels

Forward-thinking enterprises are no longer satisfied with isolated AI capabilities. The competitive advantage comes from creating sophisticated AI systems that work together, sharing information and capabilities to create comprehensive business solutions with voice agents handling the critical human touchpoints through AI phone calls. For a more detailed looked into enterprise AI voice agents, read our comprehensive 2025 B2B Guide to AI Phone Calls.

With Retell AI's voice agents connected to your existing AI assistant, you're positioning your organization at the forefront of this AI integration revolution, creating new possibilities for automation, customer engagement, and operational efficiency like never seen before.

Ready to see how Retell AI can transform your business communication? Contact our team for a personalized demonstration and discover the full potential of AI voice agents for your specific needs.

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ROI Result

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Total Human Agent Cost

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AI Agent Cost

$3,000
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Estimated Savings

$2,000
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