MCP allow you to extend your agent’s capabilities by integrating external MCPs and utilize MCP tools.

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Steps

1

Add MCP

To use MCP tools, you first need to connect your agent to the MCP server. This step will allow you to authenticate and set up the connection.Click on + Add MCP
Add MCP Configuration
2

Set request headers (optional)

You can define custom headers to include with the request Retell sends to your MCP Server.
3

Set query parameters (optional)

You can define query parameters to include in the request URL that Retell appends to your MCP Server Endpoint.
4

Select Tool

Select the MCP tool from the list of tools available
5

Set response variables (optional)

Extract values from the MCP tool response and save them as dynamic variables for use later in the conversation.For example, you can extract a user’s name from the response and reference it later using {{user_name}}.Example response body
{
  "properties": {
    "user": {
      "name": "John Doe",
      "age": 26
    }
  }
}
6

Save the MCP Tool

Click the save button
7

Update prompt for function

It’s best to include in the prompt explicitly when is the best time to invoke the mcp tool. For example:
When user states his name and phone number, please call tool `verify_user` function.