retellai

RetellAI MCP Server exposes a set of tools to manage calls, agents, phone numbers, and voices for RetellAI within an MCP (Model Context Protocol) workflow. It provides call management capabilities (creating and listing calls, web and phone calls), agent management (creating and updating Retell agents with various LLM configurations, versioning), phone number provisioning, and access to a catalog of Retell voices. You can invoke these tools from your MCP-enabled assistant to orchestrate outbound communications, manage agents for different personas, and configure phone numbers and voices for your interactions. The server is designed to be run via npx with the RetellAI MCP Server package and requires your Retell API key for authentication. In a Claude Desktop setup, you can point Claude’s config to this MCP server so Claude-enabled assistants can leverage RetellAI capabilities during conversations. The available tools are grouped into Call Tools, Agent Tools, Phone Number Tools, and Voice Tools, enabling a structured workflow for building conversational agents that can place calls, manage agents, and configure communication channels.

Prerequisites:

• Node.js and npm installed on your machine
• Access to RetellAI API key

Installation steps:

1. Install dependencies (from your project directory):

npm i

2. Create a configuration file or environment setup with your Retell API key. For example, create a .env file:

RETELL_API_KEY=your_api_key_here

3. Run the MCP server during development or integrate into your automation flow. The README suggests running the server via Node.js entry point when using the local code, or using the MCP server package with npx in your Claude Desktop or MCP environment:

# Using npx as described in the README (RetellAI MCP Server)
npx -y @abhaybabbar/retellai-mcp-server

4. If you prefer running directly with Node.js (for local development):

node src/retell/index.js

5. If you are configuring Claude Desktop or another MCP client, set the server reference to the provided npx package and supply your API key as an environment variable:

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

Additional notes: Ensure your environment securely stores the RETELL_API_KEY and that network access to RetellAI services is allowed from the runtime environment. If you upgrade the MCP server package, verify compatibility with your existing MCP tooling and update any environment variables as needed.

Tips and common issues:

• Always supply a valid RETELL_API_KEY; without it, API calls will fail.
• When integrating with Claude Desktop, edit claude_desktop_config.json per the README and restart Claude Desktop to apply changes.
• Use the provided tool lists (Call Tools, Agent Tools, Phone Number Tools, Voice Tools) to discover available endpoints and their required parameters.
• If you encounter authentication or network errors, confirm that the API key has the correct permissions and that the environment can reach RetellAI endpoints.
• Keep the MCP server package up to date and test changes in a staging environment before production deployment.