How to integrate Stannp MCP with Mastra AI

This guide walks you through connecting Stannp to Mastra AI using the Composio tool router. By the end, you'll have a working Stannp agent that can add new customer to holiday postcard group, import client mailing list from spreadsheet, list all available postcard templates through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Stannp account through Composio's Stannp MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Stannp is an API-driven direct mail platform for sending postcards and letters programmatically. It lets you automate physical mail delivery—no manual printing or mailing required.

32 Tools

Introduction

This guide walks you through connecting Stannp to Mastra AI using the Composio tool router. By the end, you'll have a working Stannp agent that can add new customer to holiday postcard group, import client mailing list from spreadsheet, list all available postcard templates through natural language commands.

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

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

Also integrate Stannp with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKLlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Stannp tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Stannp tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your Stannp agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

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

The Stannp MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Stannp account. It provides structured and secure access to your direct mail contacts, groups, and templates, so your agent can perform actions like managing recipient lists, importing contacts, and retrieving mailing templates on your behalf.

  • Organize and manage recipient groups: Easily create new recipient groups and add contacts, helping you segment your mailing lists for targeted direct mail campaigns.
  • Import bulk recipients efficiently: Let your agent upload and import contacts from CSV or XLS files directly into Stannp, streamlining the process of building large mailing lists.
  • Retrieve and view contact details: Instantly fetch information on specific contacts or list all your contacts, making it simple to keep track of who’s in your database.
  • Access and manage templates: Quickly list and review all available Stannp templates, so your agent can select the right one when setting up new campaigns or mailings.

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

Step by step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach Stannp through MCP.
3

Install dependencies

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

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_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 your requests to Composio
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models
5

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

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

if (!openaiAPIKey) 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 as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session
6

Create a Tool Router session for Stannp

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["stannp"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Stannp MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "stannp" for Stannp access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
7

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the Stannp toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "stannp-mastra-agent",
    instructions: "You are an AI agent with Stannp tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM
9

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\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({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        stannp: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

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

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and Stannp toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with Stannp and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

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

if (!openaiAPIKey) 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 as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["stannp"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      stannp: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "stannp-mastra-agent",
    instructions: "You are an AI agent with Stannp tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

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

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { stannp: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with Stannp through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows
TOOLS

Supported Tools

Every Stannp action and event your agent gets out of the box.

Add recipients to group

Tool to add existing recipients to a mailing list group.

Add Recipient to Group

Tool to add a recipient to a recipient group.

Cancel Postcard

Tool to cancel a postcard if processing has not started yet.

Create Campaign

Tool to create a new direct mail campaign on the platform.

Create campaign sample

Tool to produce a PDF sample of your campaign.

Create folder

Tool to create a folder in your secure file transfer area.

Create recipient group

Tool to create a new recipient group in Stannp.

Create Letter

Tool to create a letter with mail merge to insert address and variable data.

Create Postcard

Tool to create a postcard.

Create recipient selection

Tool to create a new recipient selection for targeting in Stannp.

Delete recipient group

Tool to delete a recipient group in Stannp.

Delete Recipient

Tool to permanently delete a recipient from your account.

Get Account Balance

Tool to retrieve the current account balance.

Get Campaign

Tool to retrieve details of a specific campaign.

Get Campaign Available Dates

Tool to get available dates for scheduling a campaign (up to 30 days).

Get Campaign Cost

Tool to get the estimated cost of booking a campaign.

Get Contact

Tool to retrieve details of a specific contact.

Get Current User

Tool to get information about the currently authenticated user including rate limit status.

Get Reporting Summary

Tool to get a status summary on individual items within a date range.

Import Recipients

Tool to import recipients from a CSV or XLS file into a Stannp recipient group.

List Campaigns

Tool to get a list of all campaigns.

List Contacts

Tool to list all contacts.

List Folders

Tool to get a list of folders in your secure file transfer area.

List Mailing Groups

Tool to get a list of mailing groups on your account.

List Mailpieces

Tool to retrieve mailpiece objects sent within a date range.

List Templates

Tool to list all templates associated with the account.

Merge PDF files

Tool to merge multiple PDF files into a single file.

Purge Group

Tool to remove all recipients from a mailing list.

Recalculate group

Tool to recalculate a group to ensure stats are up to date.

Remove Recipients from Group

Tool to remove recipients from a group without deleting them.

Upload File

Tool to upload a file to your secure file transfer area.

Validate Address

Tool to validate a postal address.

FRAMEWORKS

How to build Stannp MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Stannp MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Stannp MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Stannp MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Stannp MCP with Claude Cowork

Codex logo

Codex

Use Stannp MCP with Codex

OpenClaw logo

OpenClaw

Use Stannp MCP with OpenClaw

Hermes logo

Hermes

Use Stannp MCP with Hermes

CLI logo

CLI

Use Stannp MCP with CLI

Google ADK logo

Google ADK

Use Stannp MCP with Google ADK

LangChain logo

LangChain

Use Stannp MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Stannp MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Stannp MCP with LlamaIndex

CrewAI logo

CrewAI

Use Stannp MCP with CrewAI

FAQ

Frequently asked questions

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

Yes, you can. Mastra AI 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 Stannp tools.

Yes, absolutely. You can configure which Stannp 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.

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 Stannp data and credentials are handled as safely as possible.

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A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

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