# How to integrate Lob MCP with Mastra AI ```json { "title": "How to integrate Lob MCP with Mastra AI", "toolkit": "Lob", "toolkit_slug": "lob", "framework": "Mastra AI", "framework_slug": "mastra-ai", "url": "https://composio.dev/toolkits/lob/framework/mastra-ai", "markdown_url": "https://composio.dev/toolkits/lob/framework/mastra-ai.md", "updated_at": "2026-03-29T06:40:52.638Z" } ``` ## Introduction This guide walks you through connecting Lob to Mastra AI using the Composio tool router. By the end, you'll have a working Lob agent that can send a postcard to a verified address, validate this list of mailing addresses, track delivery status for recent letters through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Lob account through Composio's Lob MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Lob with - [OpenAI Agents SDK](https://composio.dev/toolkits/lob/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/lob/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/lob/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/lob/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/lob/framework/codex) - [OpenClaw](https://composio.dev/toolkits/lob/framework/openclaw) - [Hermes](https://composio.dev/toolkits/lob/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/lob/framework/cli) - [Google ADK](https://composio.dev/toolkits/lob/framework/google-adk) - [LangChain](https://composio.dev/toolkits/lob/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/lob/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/lob/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/lob/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 Lob tools - Connect Mastra's MCP client to the Composio generated MCP URL - Fetch Lob 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 Lob 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 Lob MCP server, and what's possible with it? The Lob MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Lob account. It provides structured and secure access so your agent can perform Lob operations on your behalf. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `LOB_CREATE_DOMAIN` | Create Domain | Tool to add a new custom domain for creating custom links. Use when you need to register a domain for short link customization. | | `LOB_CREATE_LINK` | Create Link | Tool to create a shortened URL from a long URL using Lob's link shortening service. Use when you need to shorten a long URL either by using a custom domain or Lob's own short domain. | | `LOB_DELETE_DOMAIN` | Delete Domain | Tool to delete a registered domain. Use only after confirming all associated links with the domain are deleted. | | `LOB_DELETE_LINK` | Delete Link | Tool to delete a shortened link. Use when you need to remove a previously created short link from the system. | | `LOB_DELETE_UPLOAD` | Delete Upload | Tool to delete an existing upload by its unique identifier. Use when you need to permanently remove an upload and its associated data. | | `LOB_GET_DOMAIN` | Get Domain | Tool to retrieve details for a single domain from Lob. Use when you need to get configuration status, redirect links, or other metadata for a specific domain. | | `LOB_GET_LINK` | Get Link | Tool to retrieve a single shortened link. Use when you need to fetch details about a specific link by its ID. | | `LOB_LIST_DOMAINS` | List Domains | Tool to retrieve a list of all created domains. Use when you need to view or manage custom domains configured for URL shortening. Supports pagination and filtering by configuration status. | | `LOB_LIST_SHORTENED_LINKS` | List Shortened Links | Tool to retrieve a list of shortened links. The list is sorted by creation date, with the most recently created appearing first. Use when you need to view all links or filter by campaign or domain. | | `LOB_LIST_QR_CODE_ANALYTICS` | List QR Code Analytics | Tool to retrieve a list of your QR codes and their analytics data. The QR codes are returned sorted by scan date, with the most recently scanned QR codes appearing first. | | `LOB_LIST_UPLOADS` | List Uploads | Tool to list uploads from Lob. Use when you need to retrieve all uploads or filter uploads by campaign ID. | | `LOB_UPDATE_LINK` | Update Link | Tool to update any properties of a shortened link. Use when you need to modify the redirect URL, title, or metadata of an existing Lob shortened link. Requires the link_id and at least the redirect_link to update. | | `LOB_VALIDATE_IDENTITY` | Validate Identity | Tool to validate whether a given name is associated with an address. Use when you need to verify identity information by checking if a recipient name matches address records. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Lob MCP server is an implementation of the Model Context Protocol that connects your AI agent to Lob. It provides structured and secure access so your agent can perform Lob 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 Lob 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 Lob What's happening: - create spins up a short-lived MCP HTTP endpoint for this user - The toolkits array contains "lob" for Lob 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: ["lob"], }, ); const composioMCPUrl = session.mcp.url; console.log("Lob 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 Lob 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: "lob-mastra-agent", instructions: "You are an AI agent with Lob 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 Lob 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: { lob: 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: ["lob"], }); const composioMCPUrl = session.mcp.url; const mcpClient = new MCPClient({ id: composioUserID as string, servers: { lob: { url: new URL(composioMCPUrl), requestInit: { headers: session.mcp.headers, }, }, }, timeout: 30_000, }); const composioTools = await mcpClient.getTools(); const agent = new Agent({ name: "lob-mastra-agent", instructions: "You are an AI agent with Lob 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: { lob: 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 Lob 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 Lob MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/lob/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/lob/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/lob/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/lob/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/lob/framework/codex) - [OpenClaw](https://composio.dev/toolkits/lob/framework/openclaw) - [Hermes](https://composio.dev/toolkits/lob/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/lob/framework/cli) - [Google ADK](https://composio.dev/toolkits/lob/framework/google-adk) - [LangChain](https://composio.dev/toolkits/lob/framework/langchain) - [Vercel AI SDK](https://composio.dev/toolkits/lob/framework/ai-sdk) - [LlamaIndex](https://composio.dev/toolkits/lob/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/lob/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. - [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. - [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. - [Beeminder](https://composio.dev/toolkits/beeminder) - Beeminder is an online goal-tracking platform that uses monetary pledges to keep you motivated. Stay accountable and hit your targets with real financial incentives. - [Boxhero](https://composio.dev/toolkits/boxhero) - Boxhero is a cloud-based inventory management platform for SMBs, offering real-time updates, barcode scanning, and team collaboration. It helps businesses streamline stock tracking and analytics for smarter inventory decisions. - [Breathe HR](https://composio.dev/toolkits/breathehr) - Breathe HR is cloud-based HR software for SMEs to manage employee data, absences, and performance. It simplifies HR admin, making it easy to keep employee records accurate and up to date. - [Breeze](https://composio.dev/toolkits/breeze) - Breeze is a project management platform designed to help teams plan, track, and collaborate on projects. It streamlines workflows and keeps everyone on the same page. - [Bugherd](https://composio.dev/toolkits/bugherd) - Bugherd is a visual feedback and bug tracking tool for websites. It helps teams and clients report website issues directly on live sites for faster fixes. - [Canny](https://composio.dev/toolkits/canny) - Canny is a platform for managing customer feedback and feature requests. It helps teams prioritize product decisions based on real user insights. - [Chmeetings](https://composio.dev/toolkits/chmeetings) - Chmeetings is a church management platform for events, members, donations, and volunteers. It streamlines church operations and improves community engagement. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Lob MCP? With a standalone Lob MCP server, the agents and LLMs can only access a fixed set of Lob tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Lob 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 Lob tools. ### Can I manage the permissions and scopes for Lob while using Tool Router? Yes, absolutely. You can configure which Lob 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 Lob data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)