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

Tool	Description
retell_create_phone_call	Create a new outbound phone call
retell_create_web_call	Create a new web call session
retell_get_call	Retrieve details of a specific call
retell_list_calls	List and filter calls
retell_update_call	Update call metadata
retell_delete_call	Delete a call

Chat Tools

Tool	Description
retell_create_chat	Create a chat session
retell_create_sms_chat	Start an SMS conversation
retell_get_chat	Get chat details
retell_create_chat_completion	Send a message
retell_list_chats	List all chats
retell_end_chat	End a chat session

Phone Number Tools

Tool	Description
retell_create_phone_number	Purchase a phone number
retell_get_phone_number	Get phone number details
retell_list_phone_numbers	List all phone numbers
retell_update_phone_number	Update phone number settings
retell_delete_phone_number	Delete a phone number
retell_import_phone_number	Import via SIP

Voice Agent Tools

Tool	Description
retell_create_agent	Create a voice agent
retell_get_agent	Get agent details
retell_list_agents	List all agents
retell_update_agent	Update agent config
retell_delete_agent	Delete an agent
retell_publish_agent	Publish agent version
retell_get_agent_versions	Get version history

Chat Agent Tools

Tool	Description
retell_create_chat_agent	Create a chat agent
retell_get_chat_agent	Get chat agent details
retell_list_chat_agents	List chat agents
retell_update_chat_agent	Update chat agent
retell_delete_chat_agent	Delete chat agent

LLM Tools

Tool	Description
retell_create_llm	Create LLM configuration
retell_get_llm	Get LLM details
retell_list_llms	List all LLMs
retell_update_llm	Update LLM config
retell_delete_llm	Delete LLM

Conversation Flow Tools

Tool	Description
retell_create_conversation_flow	Create a flow
retell_get_conversation_flow	Get flow details
retell_list_conversation_flows	List all flows
retell_update_conversation_flow	Update a flow
retell_delete_conversation_flow	Delete a flow

Knowledge Base Tools

Tool	Description
retell_create_knowledge_base	Create knowledge base
retell_get_knowledge_base	Get KB details
retell_list_knowledge_bases	List all KBs
retell_delete_knowledge_base	Delete KB
retell_add_knowledge_base_sources	Add sources
retell_delete_knowledge_base_source	Remove source

Voice Tools

Tool	Description
retell_get_voice	Get voice details
retell_list_voices	List available voices

Batch Tools

Tool	Description
retell_create_batch_call	Schedule bulk calls
retell_create_batch_test	Run agent tests

Account Tools

Tool	Description
retell_get_concurrency	Check call limits
retell_register_phone_call	Register inbound call

Example Usage

Once configured, you can use Claude to interact with Retell AI:

List available voices:

"Show me all available voices for Retell AI"

Create an agent:

"Create a new voice agent named 'Support Bot' using the voice '11labs-Adrian' with a friendly greeting"

Make a phone call:

"Call +1234567890 from my registered number +0987654321 using the Support Bot agent"

Check call history:

"Show me all calls from the last 24 hours"

Development

# Install dependencies
npm install

# Build TypeScript
npm run build

# Watch mode for development
npm run dev

License

MIT

Links

• Retell AI Documentation
• Retell AI Dashboard
• Claude Code MCP Documentation
• MCP Protocol