Retell AI MCP Server

A Model Context Protocol (MCP) server that provides tools for interacting with the Retell AI API. Build, test, deploy, and monitor AI phone agents directly through Claude or other MCP-compatible clients.

Features

This MCP server exposes 45+ tools covering all major Retell AI API endpoints:

Call Management

• Create outbound phone calls and web calls
• Retrieve call details including transcripts and recordings
• List and filter calls with pagination
• Update call metadata and data storage settings
• Delete calls and associated data

Chat Management

• Create chat sessions and SMS conversations
• Send messages and receive responses
• List and manage chat sessions

Phone Number Management

• Purchase/register new phone numbers
• Import existing numbers via SIP
• Configure inbound/outbound agents per number
• List and manage phone numbers

Agent Management

• Create and configure voice agents
• Create and configure chat agents
• Publish agent versions
• Manage agent settings (voice, language, behavior)

LLM & Conversation Flow

• Create and manage Retell LLM configurations
• Design conversation flows with node-based structure
• Configure custom prompts and function calling

Knowledge Base

• Create knowledge bases for agent context
• Add sources (URLs, text, documents)
• Manage knowledge base sources

Voice & Batch Operations

• List available voices
• Schedule batch outbound calls
• Run automated agent tests

Account

• Check concurrent call limits

Installation

npm install
npm run build

Configuration

Environment Variable

Set your Retell AI API key as an environment variable:

export RETELL_API_KEY="your-api-key-here"

Get your API key from the Retell AI Dashboard.

Claude Code Configuration

Option 1: Using the CLI (Recommended)

Add the MCP server using the claude mcp add command:

claude mcp add --transport stdio retell-ai -e RETELL_API_KEY=your-api-key-here -- node /path/to/retell-ai-mcp/dist/index.js

You can also use environment variable expansion:

claude mcp add --transport stdio retell-ai -e RETELL_API_KEY=\${RETELL_API_KEY} -- node /path/to/retell-ai-mcp/dist/index.js

Option 2: Project Configuration File

Create a .mcp.json file in your project root to share with your team:

{
  "mcpServers": {
    "retell-ai": {
      "command": "node",
      "args": ["/path/to/retell-ai-mcp/dist/index.js"],
      "env": {
        "RETELL_API_KEY": "${RETELL_API_KEY}"
      }
    }
  }
}

The ${RETELL_API_KEY} syntax will expand the environment variable at runtime.

Managing the Server

# List configured MCP servers
claude mcp list

# Get details about the retell-ai server
claude mcp get retell-ai

# Remove the server
claude mcp remove retell-ai

Claude Desktop Configuration

Add this to your Claude Desktop config file:

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

{
  "mcpServers": {
    "retell-ai": {
      "command": "node",
      "args": ["/path/to/retell-ai-mcp/dist/index.js"],
      "env": {
        "RETELL_API_KEY": "your-api-key-here"
      }
    }
  }
}

Available Tools

Call Tools

Chat Tools

Phone Number Tools

Voice Agent Tools

Chat Agent Tools

LLM Tools

Conversation Flow Tools

Knowledge Base Tools