# How to integrate Mailercloud MCP with Mastra AI ```json { "title": "How to integrate Mailercloud MCP with Mastra AI", "toolkit": "Mailercloud", "toolkit_slug": "mailercloud", "framework": "Mastra AI", "framework_slug": "mastra-ai", "url": "https://composio.dev/toolkits/mailercloud/framework/mastra-ai", "markdown_url": "https://composio.dev/toolkits/mailercloud/framework/mastra-ai.md", "updated_at": "2026-03-29T06:41:18.215Z" } ``` ## Introduction This guide walks you through connecting Mailercloud to Mastra AI using the Composio tool router. By the end, you'll have a working Mailercloud agent that can send a newsletter to all vip contacts, add a new subscriber to marketing list, get open rates for last week's campaign through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Mailercloud account through Composio's Mailercloud MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Mailercloud with - [OpenAI Agents SDK](https://composio.dev/toolkits/mailercloud/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/mailercloud/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/mailercloud/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/mailercloud/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/mailercloud/framework/codex) - [OpenClaw](https://composio.dev/toolkits/mailercloud/framework/openclaw) - [Hermes](https://composio.dev/toolkits/mailercloud/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/mailercloud/framework/cli) - [Google ADK](https://composio.dev/toolkits/mailercloud/framework/google-adk) - [LangChain](https://composio.dev/toolkits/mailercloud/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/mailercloud/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/mailercloud/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/mailercloud/framework/crew-ai) ## 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 Mailercloud tools - Connect Mastra's MCP client to the Composio generated MCP URL - Fetch Mailercloud 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 Mailercloud 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 Mailercloud MCP server, and what's possible with it? The Mailercloud MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Mailercloud account. It provides structured and secure access so your agent can perform Mailercloud operations on your behalf. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `MAILERCLOUD_CREATE_LIST` | Create List | Tool to create a new recipient list in Mailercloud for storing and managing contacts. Use when you need to create a new mailing list for organizing contacts. | | `MAILERCLOUD_CREATE_PROPERTY` | Create custom property | Create a custom property for contacts in Mailercloud. Custom properties store specific information for contact records. Maximum of 100 properties allowed per account. | | `MAILERCLOUD_DELETE_PROPERTY` | Delete Contact Property | Tool to delete a custom contact property by ID. Use when removing unused custom fields from contacts. Cannot delete properties used in webforms. | | `MAILERCLOUD_GET_CLIENT_PLAN` | Get Client Plan | Tool to retrieve client plan information from Mailercloud. Use when you need to check the current subscription status, plan details, or verify API connectivity. | | `MAILERCLOUD_SEARCH_CONTACTS_IN_LIST` | Search Contacts in List | Tool to retrieve contacts in a specific list with pagination. Use when you need to list or search contacts within a known list ID. | | `MAILERCLOUD_UPDATE_CONTACT_PROPERTY` | Update Contact Property | Tool to update a custom property of contacts in Mailercloud. Use when you need to modify the name or description of an existing custom property. Note: Editing custom property type using this API is not possible - you can only edit the name and description. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Mailercloud MCP server is an implementation of the Model Context Protocol that connects your AI agent to Mailercloud. It provides structured and secure access so your agent can perform Mailercloud operations on your behalf through a secure, permission-based interface. With Composio's managed implementation, you don't have to create your own developer app. For production, if you're building an end product, we recommend using your own credentials. The managed server helps you prototype fast and go from 0-1 faster. ## Step-by-step Guide ### 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 ### 1. Getting API Keys for OpenAI and Composio OpenAI API Key - Go to the [OpenAI dashboard](https://platform.openai.com/settings/organization/api-keys) 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](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs). - Go to Settings and copy your API key. - This key lets your Mastra agent talk to Composio and reach Mailercloud through MCP. ### 2. Install dependencies 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 ```bash npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv ``` ### 3. Set up environment variables 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 ```bash COMPOSIO_API_KEY=your_composio_api_key_here COMPOSIO_USER_ID=your_user_id_here OPENAI_API_KEY=your_openai_api_key_here ``` ### 4. Import libraries and validate environment 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 ```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, }); ``` ### 5. Create a Tool Router session for Mailercloud What's happening: - create spins up a short-lived MCP HTTP endpoint for this user - The toolkits array contains "mailercloud" for Mailercloud access - session.mcp.url is the MCP URL that Mastra's MCPClient will connect to ```typescript async function main() { const session = await composio.create( composioUserID as string, { toolkits: ["mailercloud"], }, ); const composioMCPUrl = session.mcp.url; console.log("Mailercloud MCP URL:", composioMCPUrl); ``` ### 6. Configure Mastra MCP client and fetch tools 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 Mailercloud toolkit ```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); ``` ### 7. Create the Mastra agent 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 ```typescript const agent = new Agent({ name: "mailercloud-mastra-agent", instructions: "You are an AI agent with Mailercloud tools via Composio.", model: "openai/gpt-5", }); ``` ### 8. Set up interactive chat interface What's happening: - messages keeps the full conversation history in Mastra's expected format - agent.generate runs the agent with conversation history and Mailercloud 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 ```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: { mailercloud: 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); }); ``` ## Complete Code ```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: ["mailercloud"], }); const composioMCPUrl = session.mcp.url; const mcpClient = new MCPClient({ id: composioUserID as string, servers: { mailercloud: { url: new URL(composioMCPUrl), requestInit: { headers: session.mcp.headers, }, }, }, timeout: 30_000, }); const composioTools = await mcpClient.getTools(); const agent = new Agent({ name: "mailercloud-mastra-agent", instructions: "You are an AI agent with Mailercloud 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: { mailercloud: 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 Mailercloud 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 ## How to build Mailercloud MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/mailercloud/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/mailercloud/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/mailercloud/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/mailercloud/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/mailercloud/framework/codex) - [OpenClaw](https://composio.dev/toolkits/mailercloud/framework/openclaw) - [Hermes](https://composio.dev/toolkits/mailercloud/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/mailercloud/framework/cli) - [Google ADK](https://composio.dev/toolkits/mailercloud/framework/google-adk) - [LangChain](https://composio.dev/toolkits/mailercloud/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/mailercloud/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/mailercloud/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/mailercloud/framework/crew-ai) ## Related Toolkits - [Google Sheets](https://composio.dev/toolkits/googlesheets) - Google Sheets is a cloud-based spreadsheet tool for real-time collaboration and data analysis. It lets teams work together from anywhere, updating information instantly. - [Notion](https://composio.dev/toolkits/notion) - Notion is a collaborative workspace for notes, docs, wikis, and tasks. It streamlines team knowledge, project tracking, and workflow customization in one place. - [Airtable](https://composio.dev/toolkits/airtable) - Airtable combines the flexibility of spreadsheets with the power of a database for easy project and data management. Teams use Airtable to organize, track, and collaborate with custom views and automations. - [Asana](https://composio.dev/toolkits/asana) - Asana is a collaborative work management platform for teams to organize and track projects. It streamlines teamwork, boosts productivity, and keeps everyone aligned on goals. - [Google Tasks](https://composio.dev/toolkits/googletasks) - Google Tasks is a to-do list and task management tool integrated into Gmail and Google Calendar. It helps you organize, track, and complete tasks across your Google ecosystem. - [Linear](https://composio.dev/toolkits/linear) - Linear is a modern issue tracking and project planning tool for fast-moving teams. It helps streamline workflows, organize projects, and boost productivity. - [Jira](https://composio.dev/toolkits/jira) - Jira is Atlassian’s platform for bug tracking, issue tracking, and agile project management. It helps teams organize work, prioritize tasks, and deliver projects efficiently. - [Clickup](https://composio.dev/toolkits/clickup) - ClickUp is an all-in-one productivity platform for managing tasks, docs, goals, and team collaboration. It streamlines project workflows so teams can work smarter and stay organized in one place. - [Monday](https://composio.dev/toolkits/monday) - Monday.com is a customizable work management platform for project planning and collaboration. It helps teams organize tasks, automate workflows, and track progress in real time. - [Reddit](https://composio.dev/toolkits/reddit) - Reddit is a social news platform with thriving user-driven communities (subreddits). It's the go-to place for discussion, content sharing, and viral marketing. - [Facebook](https://composio.dev/toolkits/facebook) - Facebook is a social media and advertising platform for businesses and creators. It helps you connect, share, and manage content across your public Facebook Pages. - [Linkedin](https://composio.dev/toolkits/linkedin) - LinkedIn is a professional networking platform for connecting, sharing content, and engaging with business opportunities. It's the go-to place for building your professional brand and unlocking new career connections. - [Active campaign](https://composio.dev/toolkits/active_campaign) - ActiveCampaign is a marketing automation and CRM platform for managing email campaigns, sales pipelines, and customer segmentation. It helps businesses engage customers and drive growth through smart automation and targeted outreach. - [ActiveTrail](https://composio.dev/toolkits/active_trail) - ActiveTrail is a user-friendly email marketing and automation platform. It helps you reach subscribers and automate campaigns with ease. - [Addressfinder](https://composio.dev/toolkits/addressfinder) - Addressfinder is a data quality platform for verifying addresses, emails, and phone numbers. It helps you ensure accurate customer and contact data every time. - [Agiled](https://composio.dev/toolkits/agiled) - Agiled is an all-in-one business management platform for CRM, projects, and finance. It helps you streamline workflows, consolidate client data, and manage business processes in one place. - [Ahrefs](https://composio.dev/toolkits/ahrefs) - Ahrefs is an SEO and marketing platform for site audits, keyword research, and competitor insights. It helps you improve search rankings and drive organic traffic. - [Amcards](https://composio.dev/toolkits/amcards) - AMCards lets you create and mail personalized greeting cards online. Build stronger customer relationships with easy, automated card campaigns. - [Ascora](https://composio.dev/toolkits/ascora) - Ascora is a cloud-based field service management platform for service businesses. It streamlines scheduling, invoicing, and customer operations in one place. - [Basecamp](https://composio.dev/toolkits/basecamp) - Basecamp is a project management and team collaboration tool by 37signals. It helps teams organize tasks, share files, and communicate efficiently in one place. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Mailercloud MCP? With a standalone Mailercloud MCP server, the agents and LLMs can only access a fixed set of Mailercloud tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Mailercloud and many other apps based on the task at hand, all through a single MCP endpoint. ### Can I use Tool Router MCP with Mastra AI? 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 Mailercloud tools. ### Can I manage the permissions and scopes for Mailercloud while using Tool Router? Yes, absolutely. You can configure which Mailercloud 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 Mailercloud data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)