How to integrate Smtp2go MCP with CrewAI

BOOK A CALLGET STARTED FOR FREE
Framework Integration Gradient
Smtp2go Logo
CrewAI Logo
divider

Introduction

This guide walks you through connecting Smtp2go to CrewAI using the Composio tool router. By the end, you'll have a working Smtp2go agent that can search for bounced emails this week, add marketing@mydomain.com as allowed sender, list all verified sender domains, remove old ip address from allow list through natural language commands.

This guide will help you understand how to give your CrewAI agent real control over a Smtp2go account through Composio's Smtp2go MCP server.

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

TL;DR

Here's what you'll learn:
  • Get a Composio API key and configure your Smtp2go connection
  • Set up CrewAI with an MCP enabled agent
  • Create a Tool Router session or standalone MCP server for Smtp2go
  • Build a conversational loop where your agent can execute Smtp2go operations

What is CrewAI?

CrewAI is a powerful framework for building multi-agent AI systems. It provides primitives for defining agents with specific roles, creating tasks, and orchestrating workflows through crews.

Key features include:

  • Agent Roles: Define specialized agents with specific goals and backstories
  • Task Management: Create tasks with clear descriptions and expected outputs
  • Crew Orchestration: Combine agents and tasks into collaborative workflows
  • MCP Integration: Connect to external tools through Model Context Protocol

What is the Smtp2go MCP server, and what's possible with it?

The Smtp2go MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Smtp2go account. It provides structured and secure access to your email sending and management infrastructure, so your agent can perform actions like searching email activity, managing allowed senders, updating sender domains, and controlling IP allow lists on your behalf.

  • Comprehensive email activity search: Ask your agent to filter and retrieve email events such as sends, opens, clicks, and bounces by recipient, date, or message ID.
  • Allowed sender management: Have your agent add, update, remove, or view allowed sender email addresses to control who can send emails from your account.
  • Sender domain configuration: Let the agent register new sender domains for SPF/DKIM verification and manage domain-related settings seamlessly.
  • IP allow list control: Direct your agent to add or remove IP addresses or CIDR ranges in your account’s IP allow list, enhancing security for sending sources.
  • Email delivery monitoring: Enable your agent to search and analyze sent emails, helping you monitor delivery, troubleshoot issues, and ensure reliable communication.

Supported Tools & Triggers

Tools
Search Email ActivityTool to search activity events like sends, opens, clicks, and bounces.
Add Allowed SenderTool to add a new allowed sender email address.
Remove Allowed SenderTool to remove a sender email address from the allowed senders list.
Update Allowed SenderTool to update details of an existing allowed sender.
View Allowed SendersTool to view the list of allowed senders configured in your account.
Add Sender DomainTool to add a new sender domain for spf/dkim verification.
Search SMTP2GO EmailsTool to search sent emails.
Add IP Allow ListTool to add an ip address or cidr range to your account’s ip allow list.
Remove IP from Allow ListTool to remove an ip address from your account's ip allow list.
View IP Allow ListTool to view the list of ip addresses in your ip allow list.
View Received SMSTool to retrieve received sms replies for your smtp2go account.
Get Email Bounces StatsTool to retrieve email bounces statistics.
Email Cycle StatisticsTool to retrieve email cycle statistics.
Email History StatisticsTool to retrieve email history statistics.
Email Spam StatisticsTool to retrieve email spam report statistics.
Email Unsubscription StatsTool to retrieve email unsubscribe statistics.
Search SubaccountsTool to search subaccounts.
Subaccounts UsageTool to retrieve usage statistics for subaccounts.
Add to Suppression ListTool to add email addresses or domains to the suppression list.
Remove suppression entryTool to remove an email address or domain from the suppression list.
View Suppression ListTool to view the suppression list.
Edit Email TemplateTool to edit details of an existing email template.
Search Email TemplatesTool to search your collection of email templates by id or name.
View Email TemplateTool to view details of a specific email template.
Add SMTP UserTool to add a new smtp user.
Edit SMTP UserTool to edit details of an existing smtp user.
Remove SMTP UserTool to remove an smtp user from your account.
View SMTP UsersTool to list all smtp users configured on your account.
Add WebhookTool to create a new webhook.
Edit WebhookTool to edit an existing webhook’s settings.
Remove webhookTool to remove a webhook.
View WebhooksTool to view all webhooks configured in your account.

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

What is Tool Router?

Composio's Tool Router 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 Tool Router

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

How the Tool Router works

The Tool Router 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 starting, make sure you have:
  • Python 3.9 or higher
  • A Composio account and API key
  • A Smtp2go connection authorized in Composio
  • An OpenAI API key for the CrewAI LLM
  • Basic familiarity with Python

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 dependencies

bash
pip install composio crewai crewai-tools python-dotenv
What's happening:
  • composio connects your agent to Smtp2go via MCP
  • crewai provides Agent, Task, Crew, and LLM primitives
  • crewai-tools includes MCP helpers
  • python-dotenv loads environment variables from .env

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates with Composio
  • USER_ID scopes the session to your account
  • OPENAI_API_KEY lets CrewAI use your chosen OpenAI model

Import dependencies

python
from crewai import Agent, Task, Crew, LLM
from crewai_tools import MCPServerAdapter  # optional import if you plan to adapt tools
from composio import Composio
from dotenv import load_dotenv
import os
from crewai.mcp import MCPServerHTTP

load_dotenv()
What's happening:
  • CrewAI classes define agents and tasks, and run the workflow
  • MCPServerHTTP connects the agent to an MCP endpoint
  • Composio will give you a short lived Smtp2go MCP URL

Create a Composio Tool Router session for Smtp2go

python
composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
session = composio.create(
    user_id=os.getenv("USER_ID"),
    toolkits=["smtp2go"],
)
url = session.mcp.url
What's happening:
  • You create a Smtp2go only session through Composio
  • Composio returns an MCP HTTP URL that exposes Smtp2go tools

Configure the LLM

python
llm = LLM(
    model="gpt-5-mini",
    api_key=os.getenv("OPENAI_API_KEY"),
)
What's happening:
  • CrewAI will call this LLM for planning and responses
  • You can swap in a different model if needed

Attach the MCP server and create the agent

python
toolkit_agent = Agent(
    role="Smtp2go Assistant",
    goal="Help users interact with Smtp2go through natural language commands",
    backstory=(
        "You are an expert assistant with access to Smtp2go tools. "
        "You can perform various Smtp2go operations on behalf of the user."
    ),
    mcps=[
        MCPServerHTTP(
            url=url,
            streamable=True,
            cache_tools_list=True,
            headers={"x-api-key": os.getenv("COMPOSIO_API_KEY")},
        ),
    ],
    llm=llm,
    verbose=True,
    max_iter=10,
)
What's happening:
  • MCPServerHTTP connects the agent to the Smtp2go MCP endpoint
  • cache_tools_list saves a tools catalog for faster subsequent runs
  • verbose helps you see what the agent is doing

Add a REPL loop with Task and Crew

python
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to perform Smtp2go operations.\n")

conversation_context = ""

while True:
    user_input = input("You: ").strip()

    if user_input.lower() in ["exit", "quit", "bye"]:
        print("\nGoodbye!")
        break

    if not user_input:
        continue

    conversation_context += f"\nUser: {user_input}\n"
    print("\nAgent is thinking...\n")

    task = Task(
        description=(
            f"Based on the conversation history:\n{conversation_context}\n\n"
            f"Current user request: {user_input}\n\n"
            f"Please help the user with their Smtp2go related request."
        ),
        expected_output="A helpful response addressing the user's request",
        agent=toolkit_agent,
    )

    crew = Crew(
        agents=[toolkit_agent],
        tasks=[task],
        verbose=False,
    )

    result = crew.kickoff()
    response = str(result)

    conversation_context += f"Agent: {response}\n"
    print(f"Agent: {response}\n")
What's happening:
  • You build a simple chat loop and keep a running context
  • Each user turn becomes a Task handled by the same agent
  • Crew executes the task and returns a response

Run the application

python
if __name__ == "__main__":
    main()
What's happening:
  • Standard Python entry point so you can run python crewai_smtp2go_agent.py

Complete Code

Here's the complete code to get you started with Smtp2go and CrewAI:

python
# file: crewai_smtp2go_agent.py
from crewai import Agent, Task, Crew, LLM
from crewai_tools import MCPServerAdapter  # optional
from composio import Composio
from dotenv import load_dotenv
import os
from crewai.mcp import MCPServerHTTP

load_dotenv()

def main():
    # Initialize Composio and create a Smtp2go session
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
    session = composio.create(
        user_id=os.getenv("USER_ID"),
        toolkits=["smtp2go"],
    )
    url = session.mcp.url

    # Configure LLM
    llm = LLM(
        model="gpt-5-mini",
        api_key=os.getenv("OPENAI_API_KEY"),
    )

    # Create Smtp2go assistant agent
    toolkit_agent = Agent(
        role="Smtp2go Assistant",
        goal="Help users interact with Smtp2go through natural language commands",
        backstory=(
            "You are an expert assistant with access to Smtp2go tools. "
            "You can perform various Smtp2go operations on behalf of the user."
        ),
        mcps=[
            MCPServerHTTP(
                url=url,
                streamable=True,
                cache_tools_list=True,
                headers={"x-api-key": os.getenv("COMPOSIO_API_KEY")},
            ),
        ],
        llm=llm,
        verbose=True,
        max_iter=10,
    )

    print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
    print("Try asking the agent to perform Smtp2go operations.\n")

    conversation_context = ""

    while True:
        user_input = input("You: ").strip()

        if user_input.lower() in ["exit", "quit", "bye"]:
            print("\nGoodbye!")
            break

        if not user_input:
            continue

        conversation_context += f"\nUser: {user_input}\n"
        print("\nAgent is thinking...\n")

        task = Task(
            description=(
                f"Based on the conversation history:\n{conversation_context}\n\n"
                f"Current user request: {user_input}\n\n"
                f"Please help the user with their Smtp2go related request."
            ),
            expected_output="A helpful response addressing the user's request",
            agent=toolkit_agent,
        )

        crew = Crew(
            agents=[toolkit_agent],
            tasks=[task],
            verbose=False,
        )

        result = crew.kickoff()
        response = str(result)

        conversation_context += f"Agent: {response}\n"
        print(f"Agent: {response}\n")

if __name__ == "__main__":
    main()

Conclusion

You now have a CrewAI agent connected to Smtp2go through Composio's Tool Router. The agent can perform Smtp2go operations through natural language commands. Next steps:
  • Add role-specific instructions to customize agent behavior
  • Plug in more toolkits for multi-app workflows
  • Chain tasks for complex multi-step operations

How to build Smtp2go MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Smtp2go MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Smtp2go MCP with Claude Agent SDK

Google ADK

Google ADK

Use Smtp2go MCP with Google ADK

LangChain

LangChain

Use Smtp2go MCP with LangChain

Vercel AI SDK

Vercel AI SDK

Use Smtp2go MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Smtp2go MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Smtp2go MCP with LlamaIndex

FAQ

What are the differences in Tool Router MCP and Smtp2go MCP?

With a standalone Smtp2go MCP server, the agents and LLMs can only access a fixed set of Smtp2go tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Smtp2go and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with CrewAI?

Yes, you can. CrewAI 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 Smtp2go tools.

Can I manage the permissions and scopes for Smtp2go while using Tool Router?

Yes, absolutely. You can configure which Smtp2go 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 Smtp2go data and credentials are handled as safely as possible.

Used by agents from

Context
ASU
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
ASU
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
ASU
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

Never worry about agent reliability

We handle tool reliability, observability, and security so you never have to second-guess an agent action.

Book a call↗Get started for free