How to integrate Etermin MCP with Vercel AI SDK v6

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Introduction

This guide walks you through connecting Etermin to Vercel AI SDK v6 using the Composio tool router. By the end, you'll have a working Etermin agent that can add new client contact for booking, remove canceled appointment from calendar, create voucher for returning customer through natural language commands.

This guide will help you understand how to give your Vercel AI SDK agent real control over a Etermin account through Composio's Etermin MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Etermin with

TL;DR

Here's what you'll learn:
  • How to set up and configure a Vercel AI SDK agent with Etermin integration
  • Using Composio's Tool Router to dynamically load and access Etermin tools
  • Creating an MCP client connection using HTTP transport
  • Building an interactive CLI chat interface with conversation history management
  • Handling tool calls and results within the Vercel AI SDK framework

What is Vercel AI SDK?

The Vercel AI SDK is a TypeScript library for building AI-powered applications. It provides tools for creating agents that can use external services and maintain conversation state.

Key features include:

  • streamText: Core function for streaming responses with real-time tool support
  • MCP Client: Built-in support for Model Context Protocol via @ai-sdk/mcp
  • Step Counting: Control multi-step tool execution with stopWhen: stepCountIs()
  • OpenAI Provider: Native integration with OpenAI models

What is the Etermin MCP server, and what's possible with it?

The Etermin MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Etermin account. It provides structured and secure access to your appointment scheduling system, so your agent can perform actions like creating contacts, managing bookings, updating resources, and handling calendar events on your behalf.

  • Automated contact and user creation: Instantly add new clients or team members to your Etermin account, streamlining onboarding and customer management.
  • Effortless appointment and calendar management: Let your agent delete existing appointments or calendars, freeing up schedules and reducing manual work.
  • Resource and service administration: Automatically create or remove resources and services, ensuring your booking system stays current as your business evolves.
  • Voucher and webhook setup: Quickly generate new vouchers for promotions or set up webhooks for real-time event notifications and integrations.
  • Contact and service deletion: Easily remove outdated contacts or services, keeping your scheduling platform organized and clutter-free.

Supported Tools & Triggers

Tools
Assign Calendar ServiceTool to assign a service to a calendar in eTermin.
Create AbsenceTool to create an absence (non-working time) for a specific calendar.
Create AnchortimeTool to create anchortimes (recurring time slots) in a calendar.
Create Anchortime by DateTool to create anchortimes by date.
Create AppointmentTool to create a new appointment in eTermin.
Create Appointment via SyncTool to create an appointment via sync in eTermin.
Create Calendar Return TimeTool to create a return time for a calendar.
Create ContactTool to create a new contact in eTermin.
Create ServiceTool to create a new service in eTermin.
Create Service GroupTool to create a new service group in eTermin.
Create UserTool to create a new user.
Create UsermappingTool to create a new usermapping in eTermin.
Create VoucherCreates a new discount voucher in eTermin.
Create WebhookCreates a webhook (web push notification) in eTermin to receive real-time updates about appointments.
Create Working TimeTool to create a new working time slot in eTermin.
Create Working Times DateTool to create a working times date slot for a calendar.
Delete AbsenceTool to delete an absence (non-working time) from a calendar.
Delete AnchortimeDelete an anchortime from eTermin by its ID.
Delete Anchortime By DateDelete an anchortime by date using its ID.
Delete AppointmentDelete an existing appointment by its ID.
Delete Appointment via SyncTool to delete appointments via the sync endpoint.
Delete CalendarDelete a calendar from your eTermin account.
Delete Calendar Return TimeDelete a return time from a calendar.
Delete Calendar ServiceDelete an assigned service from a calendar in eTermin.
Delete ContactDelete a contact from your eTermin account by its contact ID.
Delete ResourceDelete an eTermin resource by type and ID.
Delete ServicePermanently deletes a service from your eTermin account by its ID.
Delete Service GroupDelete a service group from your eTermin account by its ID.
Delete UserDeletes an existing user from the eTermin account.
Delete UsermappingDelete a usermapping by its ID.
Delete VoucherPermanently deletes a voucher from eTermin by its voucher code.
Delete WebhookDelete an existing webhook by its unique identifier.
Delete Working TimesTool to delete working times from a calendar.
Delete Working Times DateTool to delete working times date entries from eTermin.
Get AbsencesTool to retrieve absences (non-working times) for a specific calendar.
Get Anchortime by DateTool to retrieve anchortimes by date.
Get AnchortimesTool to retrieve anchortime details.
Get Appointment SyncTool to synchronize appointments incrementally from eTermin.
Get Bookingpage LogsTool to retrieve bookingpage request logs from eTermin.
Get Calendar Return TimeTool to retrieve return times for a specific calendar.
Get CalendarsTool to retrieve calendars.
Get Calendar Service AssignmentsTool to retrieve calendar service assignments.
Get CompanyTool to retrieve company account details.
Get Contact By IDTool to retrieve a specific contact by ID, external ID, or email.
Get ContactsTool to retrieve a list of contacts.
Get Deleted AppointmentsTool to retrieve a list of deleted appointments from eTermin.
Get Message LogsTool to retrieve message logs from eTermin.
Get Customer RatingsTool to retrieve a list of customer ratings from eTermin.
Get Service By IDTool to retrieve a specific service from eTermin.
Get Service CalendarTool to retrieve calendars for a specific service ID.
Get Service GroupTool to retrieve service group details from eTermin.
Get ServicesTool to retrieve a list of services.
Get Survey ResultsTool to retrieve survey results from eTermin.
Get TimeslotsTool to retrieve available timeslots for a specific calendar on a given date.
Get UsermappingTool to retrieve usermapping information.
Get UsersTool to retrieve a list of users.
Get Working TimesTool to retrieve working times for a specific calendar.
Get Working Times DateTool to retrieve working times for a specific calendar on a specific date.
List AppointmentsTool to retrieve a filtered list of appointments from eTermin in a specified date range.
List VouchersRetrieve all vouchers (discount codes) from your eTermin account.
List WebhooksTool to retrieve webhooks.
Update Service via PUTTool to update a service in eTermin.
Update AbsenceTool to update an absence (non-working time) for a calendar in eTermin.
Update AnchortimeUpdate an existing anchortime in eTermin.
Update Anchortime By DateTool to update anchortimes by date in eTermin.
Update AppointmentTool to update an existing appointment in eTermin.
Update CalendarUpdate an existing calendar in eTermin.
Update Calendar Return TimeTool to update a return time for a calendar in eTermin.
Update ContactTool to update an existing contact in eTermin.
Update ResourceUpdate an existing eTermin resource (contact, service, calendar, user, or voucher).
Update ServiceTool to update an existing service.
Update Service GroupTool to update an existing service group in eTermin.
Update Synchronised AppointmentTool to update a synchronised appointment in eTermin.
Update UsermappingUpdate an existing usermapping in eTermin.
Update VoucherUpdates an existing voucher in eTermin.
Update WebhookUpdate an existing webhook configuration in eTermin.
Update Working TimesTool to update working times for a calendar in eTermin.
Update Working Times DateTool to update working times date for a calendar.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Prerequisites

Before you begin, make sure you have:
  • Node.js and npm installed
  • A Composio account with API key
  • An OpenAI API key

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.

Install required dependencies

bash
npm install @ai-sdk/openai @ai-sdk/mcp @composio/core ai dotenv

First, install the necessary packages for your project.

What you're installing:

  • @ai-sdk/openai: Vercel AI SDK's OpenAI provider
  • @ai-sdk/mcp: MCP client for Vercel AI SDK
  • @composio/core: Composio SDK for tool integration
  • ai: Core Vercel AI SDK
  • dotenv: Environment variable management

Set up environment variables

bash
OPENAI_API_KEY=your_openai_api_key_here
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_user_id_here

Create a .env file in your project root.

What's needed:

  • OPENAI_API_KEY: Your OpenAI API key for GPT model access
  • COMPOSIO_API_KEY: Your Composio API key for tool access
  • COMPOSIO_USER_ID: A unique identifier for the user session

Import required modules and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Composio } from "@composio/core";
import * as readline from "readline";
import { streamText, type ModelMessage, stepCountIs } from "ai";
import { createMCPClient } from "@ai-sdk/mcp";

const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!process.env.OPENAI_API_KEY) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey,
});
What's happening:
  • We're importing all necessary libraries including Vercel AI SDK's OpenAI provider and Composio
  • The dotenv/config import automatically loads environment variables
  • The MCP client import enables connection to Composio's tool server

Create Tool Router session and initialize MCP client

typescript
async function main() {
  // Create a tool router session for the user
  const session = await composio.create(composioUserID!, {
    toolkits: ["etermin"],
  });

  const mcpUrl = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to Etermin tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned mcp object contains the URL and authentication headers needed to connect to the MCP server
  • This session provides access to all Etermin-related tools through the MCP protocol

Connect to MCP server and retrieve tools

typescript
const mcpClient = await createMCPClient({
  transport: {
    type: "http",
    url: mcpUrl,
    headers: session.mcp.headers, // Authentication headers for the Composio MCP server
  },
});

const tools = await mcpClient.tools();
What's happening:
  • We're creating an MCP client that connects to our Composio Tool Router session via HTTP
  • The mcp.url provides the endpoint, and mcp.headers contains authentication credentials
  • The type: "http" is important - Composio requires HTTP transport
  • tools() retrieves all available Etermin tools that the agent can use

Initialize conversation and CLI interface

typescript
let messages: ModelMessage[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log(
  "Ask any questions related to etermin, like summarize my last 5 emails, send an email, etc... :)))\n",
);

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: "> ",
});

rl.prompt();
What's happening:
  • We initialize an empty messages array to maintain conversation history
  • A readline interface is created to accept user input from the command line
  • Instructions are displayed to guide the user on how to interact with the agent

Handle user input and stream responses with real-time tool feedback

typescript
rl.on("line", async (userInput: string) => {
  const trimmedInput = userInput.trim();

  if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
    console.log("\nGoodbye!");
    rl.close();
    process.exit(0);
  }

  if (!trimmedInput) {
    rl.prompt();
    return;
  }

  messages.push({ role: "user", content: trimmedInput });
  console.log("\nAgent is thinking...\n");

  try {
    const stream = streamText({
      model: openai("gpt-5"),
      messages,
      tools,
      toolChoice: "auto",
      stopWhen: stepCountIs(10),
      onStepFinish: (step) => {
        for (const toolCall of step.toolCalls) {
          console.log(`[Using tool: ${toolCall.toolName}]`);
          }
          if (step.toolCalls.length > 0) {
            console.log(""); // Add space after tool calls
          }
        },
      });

      for await (const chunk of stream.textStream) {
        process.stdout.write(chunk);
      }

      console.log("\n\n---\n");

      // Get final result for message history
      const response = await stream.response;
      if (response?.messages?.length) {
        messages.push(...response.messages);
      }
    } catch (error) {
      console.error("\nAn error occurred while talking to the agent:");
      console.error(error);
      console.log(
        "\nYou can try again or restart the app if it keeps happening.\n",
      );
    } finally {
      rl.prompt();
    }
  });

  rl.on("close", async () => {
    await mcpClient.close();
    console.log("\n👋 Session ended.");
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • We use streamText instead of generateText to stream responses in real-time
  • toolChoice: "auto" allows the model to decide when to use Etermin tools
  • stopWhen: stepCountIs(10) allows up to 10 steps for complex multi-tool operations
  • onStepFinish callback displays which tools are being used in real-time
  • We iterate through the text stream to create a typewriter effect as the agent responds
  • The complete response is added to conversation history to maintain context
  • Errors are caught and displayed with helpful retry suggestions

Complete Code

Here's the complete code to get you started with Etermin and Vercel AI SDK:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Composio } from "@composio/core";
import * as readline from "readline";
import { streamText, type ModelMessage, stepCountIs } from "ai";
import { createMCPClient } from "@ai-sdk/mcp";

const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!process.env.OPENAI_API_KEY) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey,
});

async function main() {
  // Create a tool router session for the user
  const session = await composio.create(composioUserID!, {
    toolkits: ["etermin"],
  });

  const mcpUrl = session.mcp.url;

  const mcpClient = await createMCPClient({
    transport: {
      type: "http",
      url: mcpUrl,
      headers: session.mcp.headers, // Authentication headers for the Composio MCP server
    },
  });

  const tools = await mcpClient.tools();

  let messages: ModelMessage[] = [];

  console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
  console.log(
    "Ask any questions related to etermin, like summarize my last 5 emails, send an email, etc... :)))\n",
  );

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: "> ",
  });

  rl.prompt();

  rl.on("line", async (userInput: string) => {
    const trimmedInput = userInput.trim();

    if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
      console.log("\nGoodbye!");
      rl.close();
      process.exit(0);
    }

    if (!trimmedInput) {
      rl.prompt();
      return;
    }

    messages.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    try {
      const stream = streamText({
        model: openai("gpt-5"),
        messages,
        tools,
        toolChoice: "auto",
        stopWhen: stepCountIs(10),
        onStepFinish: (step) => {
          for (const toolCall of step.toolCalls) {
            console.log(`[Using tool: ${toolCall.toolName}]`);
          }
          if (step.toolCalls.length > 0) {
            console.log(""); // Add space after tool calls
          }
        },
      });

      for await (const chunk of stream.textStream) {
        process.stdout.write(chunk);
      }

      console.log("\n\n---\n");

      // Get final result for message history
      const response = await stream.response;
      if (response?.messages?.length) {
        messages.push(...response.messages);
      }
    } catch (error) {
      console.error("\nAn error occurred while talking to the agent:");
      console.error(error);
      console.log(
        "\nYou can try again or restart the app if it keeps happening.\n",
      );
    } finally {
      rl.prompt();
    }
  });

  rl.on("close", async () => {
    await mcpClient.close();
    console.log("\n👋 Session ended.");
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});

Conclusion

You've successfully built a Etermin agent using the Vercel AI SDK with streaming capabilities! This implementation provides a powerful foundation for building AI applications with natural language interfaces and real-time feedback.

Key features of this implementation:

  • Real-time streaming responses for a better user experience with typewriter effect
  • Live tool execution feedback showing which tools are being used as the agent works
  • Dynamic tool loading through Composio's Tool Router with secure authentication
  • Multi-step tool execution with configurable step limits (up to 10 steps)
  • Comprehensive error handling for robust agent execution
  • Conversation history maintenance for context-aware responses

You can extend this further by adding custom error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.

How to build Etermin MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and Etermin MCP?

With a standalone Etermin MCP server, the agents and LLMs can only access a fixed set of Etermin tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Etermin and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Vercel AI SDK v6?

Yes, you can. Vercel AI SDK v6 fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Etermin tools.

Can I manage the permissions and scopes for Etermin while using Tool Router?

Yes, absolutely. You can configure which Etermin scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Etermin data and credentials are handled as safely as possible.

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