About RetellAI MCP Server
RetellAI MCP Server is an MCP server for the RetellAI voice service, letting AI assistants manage calls, voice agents, phone numbers and voices. It suits users who want MCP clients to configure or operate RetellAI voice features.
Key features
- 01Create, list, get and delete calls
- 02Create and update voice agents
- 03View and configure phone numbers
- 04Query available voice options
Use cases
- 01Listing phone numbers and voice agents in an account
- 02Creating outbound phone calls or web calls
- 03Configuring voice agents with different LLM settings
MCP support
This is an MCP server that exposes RetellAI call, agent, phone number and voice tools to MCP clients, so AI assistants can operate the RetellAI service.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
npx -y @abhaybabbar/retellai-mcp-serverRETELL_API_KEYSecretLocal servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.
Tools
24Saved tool list · updated 3w ago
| Parameter | Type | Required | Description |
|---|---|---|---|
| metadata | object | No | |
| toNumber | string | Yes | The phone number to call to |
| direction | enum | No | inbound | outbound |
| fromNumber | string | Yes | The phone number to call from |
| optInSignedUrl | boolean | No | |
| overrideAgentId | string | No | For this particular call, override the agent used with this agent id |
| overrideAgentVersion | number | No | For this particular call, override the agent version used with this version |
| retellLlmDynamicVariables | object | No | Dynamic variables to pass to the LLM in key-value pairs |
| optOutSensitiveDataStorage | boolean | No |
Details
From the project READMERetellAI MCP Server
This is a Model Context Protocol (MCP) server implementation for RetellAI, allowing AI assistants to interact with RetellAI's voice services.
Features
The RetellAI MCP server provides tools for:
- Call Management: Create and manage phone calls and web calls
- Agent Management: Create and manage voice agents with different LLM configurations
- Phone Number Management: Provision and configure phone numbers
- Voice Management: Access and use different voice options
Claude Desktop Setup
- Open
Claude Desktopand pressCMD + ,to go toSettings. - Click on the
Developertab. - Click on the
Edit Configbutton. - This will open the
claude_desktop_config.jsonfile in your file explorer. - Get your Retell API key from the Retell dashboard (https://dashboard.retellai.com/apiKey).
- Add the following to your
claude_desktop_config.jsonfile. See here for more details. - Restart the Claude Desktop after editing the config file.
{
"mcpServers": {
"retellai-mcp-server": {
"command": "npx",
"args": ["-y", "@abhaybabbar/retellai-mcp-server"],
"env": {
"RETELL_API_KEY": "<your_retellai_token>"
}
}
}
}
Troubleshooting: "No tools available"
If Claude Desktop shows the server but no tools, upgrade to the latest package version:
npx -y @abhaybabbar/retellai-mcp-server@latest
This issue is typically caused by dependency/version mismatch in older installs.
Example use cases:
- List all the numbers I have in retellai
- List all the agents I have
- Tell me more about pizza delivery agent
- Creating agent and calling example:
- Create an agent that calls my local pizza shop, make sure to keep the conversation short and to the point.
- Order a margeritta pizza
- Payment will be done by cash on delivery
- Send it to
- 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
Repo Setup
-
Install dependencies:
npm i -
Create a
.envfile with your RetellAI API key:RETELL_API_KEY=your_api_key_here -
Run the server:
node src/retell/index.js
Available Tools
Call Tools
list_calls: Lists all Retell callscreate_phone_call: Creates a new phone callcreate_web_call: Creates a new web callget_call: Gets details of a specific calldelete_call: Deletes a specific call
Agent Tools
list_agents: Lists all Retell agentscreate_agent: Creates a new Retell agentget_agent: Gets a Retell agent by IDupdate_agent: Updates an existing Retell agentdelete_agent: Deletes a Retell agentget_agent_versions: Gets all versions of a Retell agent
Phone Number Tools
list_phone_numbers: Lists all Retell phone numberscreate_phone_number: Creates a new phone numberget_phone_number: Gets details of a specific phone numberupdate_phone_number: Updates a phone numberdelete_phone_number: Deletes a phone number
Voice Tools
list_voices: Lists all available Retell voicesget_voice: Gets details of a specific voice
License
MIT
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.