How to integrate Postgrid MCP with OpenAI Agents SDK

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Introduction

This guide walks you through connecting Postgrid to the OpenAI Agents SDK using the Composio tool router. By the end, you'll have a working Postgrid agent that can send a letter to new customer address, verify and standardize a shipping address, create a reusable postcard template through natural language commands.

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

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

Also integrate Postgrid with

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Install the necessary dependencies
  • Initialize Composio and create a Tool Router session for Postgrid
  • Configure an AI agent that can use Postgrid as a tool
  • Run a live chat session where you can ask the agent to perform Postgrid operations

What is OpenAI Agents SDK?

The OpenAI Agents SDK is a lightweight framework for building AI agents that can use tools and maintain conversation state. It provides a simple interface for creating agents with hosted MCP tool support.

Key features include:

  • Hosted MCP Tools: Connect to external services through hosted MCP endpoints
  • SQLite Sessions: Persist conversation history across interactions
  • Simple API: Clean interface with Agent, Runner, and tool configuration
  • Streaming Support: Real-time response streaming for interactive applications

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

The Postgrid MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Postgrid account. It provides structured and secure access to your direct mail and address automation tools, so your agent can verify addresses, send letters, manage contacts, and handle templates for your business communications—all without manual intervention.

  • Automated letter sending: Have your agent create and send physical letters on demand, handling recipient, sender, and content details seamlessly.
  • Contact management: Effortlessly add, update, or delete contacts in your Postgrid account to keep your mailing lists accurate and up to date.
  • Template creation and maintenance: Let your agent generate reusable mail templates with dynamic placeholders, and remove outdated templates as needed.
  • Bank account and payment management: Create or delete bank accounts associated with print and mail services, ensuring smooth financial operations for mail automation.
  • Webhook setup and monitoring: Enable your agent to create or remove webhooks to track events and receive real-time notifications for your mail orders and services.

Supported Tools & Triggers

Tools
Cancel BoxTool to cancel a box order by its ID.
Cancel ChequeTool to cancel a cheque order by its ID.
Cancel Cheque with NoteTool to cancel a cheque order with a cancellation note.
Cancel PostcardTool to cancel a postcard order.
Cancel Postcard With NoteTool to cancel a postcard order with an optional cancellation note.
Cancel Return Envelope OrderTool to cancel a return envelope order.
CREATE_BANK_ACCOUNTTool to create a new bank account for print & mail service.
Create BoxTool to create a box mailing order for letters with plastic cards or cheques.
Create ChequeTool to create a cheque order for physical cheque mailing.
Create ContactTool to create a new contact in PostGrid.
Create LetterTool to create and send a letter via PostGrid.
Create PostcardTool to create and send a postcard via PostGrid.
Create Return EnvelopeTool to create a return envelope for mail recipients to respond.
Create Return Envelope OrderTool to create a batch order of return envelopes to be printed and delivered.
Create TemplateTool to create a new mail template in PostGrid.
Create Template Editor SessionTool to create a template editor session for interactive template editing.
Create TrackerTool to create a tracker for monitoring mail delivery status via URL tracking.
Create WebhookTool to create a new webhook to receive order event notifications.
Delete Bank AccountTool to delete a bank account by its ID.
Delete ContactTool to delete a contact by its ID.
Delete TemplateTool to delete a template by its ID.
Delete Template Editor SessionTool to delete a template editor session by its ID.
Delete TrackerTool to delete a tracker by its ID.
Delete WebhookTool to delete a webhook subscription.
Fill Test Return Envelope OrderTool to fill a test return envelope order for testing purposes.
Get Bank AccountTool to retrieve a bank account.
Get BoxTool to retrieve a specific box order by ID.
Get ChequeTool to retrieve a specific cheque by ID.
Get ContactTool to retrieve a contact.
Get LetterTool to retrieve a letter.
Get PostcardTool to retrieve a specific postcard by ID.
Get Return EnvelopeTool to retrieve a return envelope.
Get Return Envelope OrderTool to retrieve a specific return envelope order.
Get TemplateTool to retrieve a template.
Get TrackerTool to retrieve a tracker.
Get WebhookTool to retrieve details of a specific webhook by its ID.
List Bank AccountsTool to list bank accounts.
List Box OrdersTool to list box orders.
List ChequesTool to list cheques with optional filters and pagination.
List ContactsTool to list contacts.
List Webhook EventsTool to retrieve a list of webhook events with optional pagination.
List LettersTool to list letters.
List Postal StatementsTool to list all postal statements for billing and tracking purposes.
List PostcardsTool to retrieve a list of postcards with optional filtering and pagination.
List Return Envelope OrdersTool to list all return envelope orders for a specific return envelope.
List Return EnvelopesTool to list return envelopes.
List Self-MailersTool to list self-mailers.
List Sub-OrganizationsTool to list sub-organizations.
List Template Editor SessionsTool to list template editor sessions.
List TemplatesTool to list templates.
List TrackersTool to list all trackers.
List Tracker VisitsTool to list all visits for a tracker.
List Webhook InvocationsTool to list previous invocations of a webhook with response status codes.
List WebhooksTool to retrieve a list of configured webhooks with optional filtering and pagination.
Progress Test BoxTool to progress a test box through processing stages for webhook testing.
Progress Test ChequeTool to progress a test cheque through processing stages for webhook testing.
Progress Test PostcardTool to progress a test postcard through processing stages for webhook testing.
Update TemplateTool to update an existing mail template in PostGrid.
Update TrackerTool to update an existing tracker's redirect URL template and/or expiration settings.
Update WebhookTool to update an existing webhook configuration.

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 starting, make sure you have:
  • Composio API Key and OpenAI API Key
  • Primary know-how of OpenAI Agents SDK
  • A live Postgrid project
  • Some knowledge of Python or Typescript

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

Install dependencies

pip install composio_openai_agents openai-agents python-dotenv

Install the Composio SDK and the OpenAI Agents SDK.

Set up environment variables

bash
OPENAI_API_KEY=sk-...your-api-key
COMPOSIO_API_KEY=your-api-key
USER_ID=composio_user@gmail.com

Create a .env file and add your OpenAI and Composio API keys.

Import dependencies

import asyncio
import os
from dotenv import load_dotenv

from composio import Composio
from composio_openai_agents import OpenAIAgentsProvider
from agents import Agent, Runner, HostedMCPTool, SQLiteSession
What's happening:
  • You're importing all necessary libraries.
  • The Composio and OpenAIAgentsProvider classes are imported to connect your OpenAI agent to Composio tools like Postgrid.

Set up the Composio instance

load_dotenv()

api_key = os.getenv("COMPOSIO_API_KEY")
user_id = os.getenv("USER_ID")

if not api_key:
    raise RuntimeError("COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key")

# Initialize Composio
composio = Composio(api_key=api_key, provider=OpenAIAgentsProvider())
What's happening:
  • load_dotenv() loads your .env file so OPENAI_API_KEY and COMPOSIO_API_KEY are available as environment variables.
  • Creating a Composio instance using the API Key and OpenAIAgentsProvider class.

Create a Tool Router session

# Create a Postgrid Tool Router session
session = composio.create(
    user_id=user_id,
    toolkits=["postgrid"]
)

mcp_url = session.mcp.url

What is happening:

  • You give the Tool Router the user id and the toolkits you want available. Here, it is only postgrid.
  • The router checks the user's Postgrid connection and prepares the MCP endpoint.
  • The returned session.mcp.url is the MCP URL that your agent will use to access Postgrid.
  • This approach keeps things lightweight and lets the agent request Postgrid tools only when needed during the conversation.

Configure the agent

# Configure agent with MCP tool
agent = Agent(
    name="Assistant",
    model="gpt-5",
    instructions=(
        "You are a helpful assistant that can access Postgrid. "
        "Help users perform Postgrid operations through natural language."
    ),
    tools=[
        HostedMCPTool(
            tool_config={
                "type": "mcp",
                "server_label": "tool_router",
                "server_url": mcp_url,
                "headers": {"x-api-key": api_key},
                "require_approval": "never",
            }
        )
    ],
)
What's happening:
  • We're creating an Agent instance with a name, model (gpt-5), and clear instructions about its purpose.
  • The agent's instructions tell it that it can access Postgrid and help with queries, inserts, updates, authentication, and fetching database information.
  • The tools array includes a HostedMCPTool that connects to the MCP server URL we created earlier.
  • The headers dict includes the Composio API key for secure authentication with the MCP server.
  • require_approval: 'never' means the agent can execute Postgrid operations without asking for permission each time, making interactions smoother.

Start chat loop and handle conversation

print("\nComposio Tool Router session created.")

chat_session = SQLiteSession("conversation_openai_toolrouter")

print("\nChat started. Type your requests below.")
print("Commands: 'exit', 'quit', or 'q' to end\n")

async def main():
    try:
        result = await Runner.run(
            agent,
            "What can you help me with?",
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")
    except Exception as e:
        print(f"Error: {e}\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "q"}:
            print("Goodbye!")
            break

        result = await Runner.run(
            agent,
            user_input,
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")

asyncio.run(main())
What's happening:
  • The program prints a session URL that you visit to authorize Postgrid.
  • After authorization, the chat begins.
  • Each message you type is processed by the agent using Runner.run().
  • The responses are printed to the console, and conversations are saved locally using SQLite.
  • Typing exit, quit, or q cleanly ends the chat.

Complete Code

Here's the complete code to get you started with Postgrid and OpenAI Agents SDK:

import asyncio
import os
from dotenv import load_dotenv

from composio import Composio
from composio_openai_agents import OpenAIAgentsProvider
from agents import Agent, Runner, HostedMCPTool, SQLiteSession

load_dotenv()

api_key = os.getenv("COMPOSIO_API_KEY")
user_id = os.getenv("USER_ID")

if not api_key:
    raise RuntimeError("COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key")

# Initialize Composio
composio = Composio(api_key=api_key, provider=OpenAIAgentsProvider())

# Create Tool Router session
session = composio.create(
    user_id=user_id,
    toolkits=["postgrid"]
)
mcp_url = session.mcp.url

# Configure agent with MCP tool
agent = Agent(
    name="Assistant",
    model="gpt-5",
    instructions=(
        "You are a helpful assistant that can access Postgrid. "
        "Help users perform Postgrid operations through natural language."
    ),
    tools=[
        HostedMCPTool(
            tool_config={
                "type": "mcp",
                "server_label": "tool_router",
                "server_url": mcp_url,
                "headers": {"x-api-key": api_key},
                "require_approval": "never",
            }
        )
    ],
)

print("\nComposio Tool Router session created.")

chat_session = SQLiteSession("conversation_openai_toolrouter")

print("\nChat started. Type your requests below.")
print("Commands: 'exit', 'quit', or 'q' to end\n")

async def main():
    try:
        result = await Runner.run(
            agent,
            "What can you help me with?",
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")
    except Exception as e:
        print(f"Error: {e}\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "q"}:
            print("Goodbye!")
            break

        result = await Runner.run(
            agent,
            user_input,
            session=chat_session
        )
        print(f"Assistant: {result.final_output}\n")

asyncio.run(main())

Conclusion

This was a starter code for integrating Postgrid MCP with OpenAI Agents SDK to build a functional AI agent that can interact with Postgrid.

Key features:

  • Hosted MCP tool integration through Composio's Tool Router
  • SQLite session persistence for conversation history
  • Simple async chat loop for interactive testing
You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.

How to build Postgrid MCP Agent with another framework

FAQ

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

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

Can I use Tool Router MCP with OpenAI Agents SDK?

Yes, you can. OpenAI Agents SDK 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 Postgrid tools.

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

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

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

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