RetellAI Voice Services MCP server

The RetellAI MCP Server is an implementation of the Model Context Protocol that enables AI assistants to interact with RetellAI's voice services. It provides functionality for managing calls, agents, phone numbers, and voice options, allowing Claude and other compatible AI assistants to make phone calls and create voice agents.

Installation

Claude Desktop Setup

1. Open Claude Desktop and press CMD + , to go to Settings
2. Click on the Developer tab
3. Click on the Edit Config button
4. Get your Retell API key from the Retell dashboard (https://dashboard.retellai.com/apiKey)
5. Add the following to your claude_desktop_config.json file:

{
  "mcpServers": {
    "retellai-mcp-server": {
      "command": "npx",
      "args": ["-y", "@abhaybabbar/retellai-mcp-server"],
      "env": {
        "RETELL_API_KEY": "<your_retellai_token>"
      }
    }
  }
}

6. Restart Claude Desktop after editing the config file

Manual Server Setup

1. Install dependencies:

npm i

2. Create a .env file with your RetellAI API key:

RETELL_API_KEY=your_api_key_here

3. Run the server:

node src/retell/index.js

Usage

Example Use Cases

You can ask Claude to perform various RetellAI-related tasks, such as:

• List all the numbers I have in RetellAI
• List all the agents I have
• Tell me more about a specific agent

Creating an Agent and Making Calls

You can instruct Claude to create agents and make calls with specific parameters:

1. "Create an agent that calls my local pizza shop, make sure to keep the conversation short and to the point."
2. Provide details for the call:
   • "Order a margherita pizza"
   • "Payment will be done by cash on delivery"
   • "Send it to [your address]"
   • "The agent should pretend to be me. My name is [your name]"
   • "Make an outbound call to my local pizza shop at [phone number], using the USA number"

Available Tools

Call Management

• list_calls: Lists all Retell calls
• create_phone_call: Creates a new phone call
• create_web_call: Creates a new web call
• get_call: Gets details of a specific call
• delete_call: Deletes a specific call

Agent Management

• list_agents: Lists all Retell agents
• create_agent: Creates a new Retell agent
• get_agent: Gets a Retell agent by ID
• update_agent: Updates an existing Retell agent
• delete_agent: Deletes a Retell agent
• get_agent_versions: Gets all versions of a Retell agent

Phone Number Management

• list_phone_numbers: Lists all Retell phone numbers
• create_phone_number: Creates a new phone number
• get_phone_number: Gets details of a specific phone number
• update_phone_number: Updates a phone number
• delete_phone_number: Deletes a phone number

Voice Management

• list_voices: Lists all available Retell voices
• get_voice: Gets details of a specific voice

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "retellai-mcp-server" '{"command":"npx","args":["-y","@abhaybabbar/retellai-mcp-server"],"env":{"RETELL_API_KEY":"<your_retellai_token>"}}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "retellai-mcp-server": {
            "command": "npx",
            "args": [
                "-y",
                "@abhaybabbar/retellai-mcp-server"
            ],
            "env": {
                "RETELL_API_KEY": "<your_retellai_token>"
            }
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "retellai-mcp-server": {
            "command": "npx",
            "args": [
                "-y",
                "@abhaybabbar/retellai-mcp-server"
            ],
            "env": {
                "RETELL_API_KEY": "<your_retellai_token>"
            }
        }
    }
}

3. Restart Claude Desktop for the changes to take effect