# How to integrate Reply MCP with Vercel AI SDK v6 ```json { "title": "How to integrate Reply MCP with Vercel AI SDK v6", "toolkit": "Reply", "toolkit_slug": "reply", "framework": "Vercel AI SDK", "framework_slug": "ai-sdk", "url": "https://composio.dev/toolkits/reply/framework/ai-sdk", "markdown_url": "https://composio.dev/toolkits/reply/framework/ai-sdk.md", "updated_at": "2026-05-12T10:23:54.555Z" } ``` ## Introduction This guide walks you through connecting Reply to Vercel AI SDK v6 using the Composio tool router. By the end, you'll have a working Reply agent that can list all active email campaigns this week, get contacts in your 'leads q3' list, show all available email templates through natural language commands. This guide will help you understand how to give your Vercel AI SDK agent real control over a Reply account through Composio's Reply MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Reply with - [OpenAI Agents SDK](https://composio.dev/toolkits/reply/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/reply/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/reply/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/reply/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/reply/framework/codex) - [OpenClaw](https://composio.dev/toolkits/reply/framework/openclaw) - [Hermes](https://composio.dev/toolkits/reply/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/reply/framework/cli) - [Google ADK](https://composio.dev/toolkits/reply/framework/google-adk) - [LangChain](https://composio.dev/toolkits/reply/framework/langchain) - [Mastra AI](https://composio.dev/toolkits/reply/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/reply/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/reply/framework/crew-ai) ## TL;DR Here's what you'll learn: - How to set up and configure a Vercel AI SDK agent with Reply integration - Using Composio's Tool Router to dynamically load and access Reply tools - Creating an MCP client connection using HTTP transport - Building an interactive CLI chat interface with conversation history management - Handling tool calls and results within the Vercel AI SDK framework ## What is Vercel AI SDK? The Vercel AI SDK is a TypeScript library for building AI-powered applications. It provides tools for creating agents that can use external services and maintain conversation state. Key features include: - streamText: Core function for streaming responses with real-time tool support - MCP Client: Built-in support for Model Context Protocol via @ai-sdk/mcp - Step Counting: Control multi-step tool execution with stopWhen: stepCountIs() - OpenAI Provider: Native integration with OpenAI models ## What is the Reply MCP server, and what's possible with it? The Reply MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Reply.io account. It provides structured and secure access to your sales engagement platform, so your agent can create and manage lists, fetch campaign schedules, organize contacts, and monitor outreach performance for you. - Personal list creation and management: Easily instruct your agent to create, organize, or delete personal contact lists to streamline your outreach workflow. - Contact organization and retrieval: Have your agent fetch contacts within specific lists, helping you target and personalize campaigns more effectively. - Campaign and schedule insights: Ask your agent to retrieve all campaign schedules or see which campaigns a specific contact belongs to, giving you up-to-date visibility into your outreach pipeline. - Email account and template discovery: Let your agent pull a list of available email accounts or fetch your personal, team, and community templates for quick access while composing new campaigns. - Blacklist monitoring and management: Direct your agent to retrieve the full list of blacklisted domains and emails, so you can ensure compliance and maintain deliverability standards with ease. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `REPLY_CREATE_LIST` | Create Personal List | Tool to add a new personal list on the People page. Use when you need to organize contacts into a custom list. | | `REPLY_DELETE_EMAIL_ACCOUNT` | Delete Email Account | Tool to delete a specific email account. Use when you need to remove an existing email account identified by its ID. | | `REPLY_DELETE_LIST_BY_ID` | Delete List By ID | Tool to delete a list by its ID. Use when you need to remove a personal list you own. | | `REPLY_DELETE_SEQUENCE` | Delete Sequence | Tool to delete a sequence. Use after confirming the sequence exists to remove it permanently. | | `REPLY_DELETE_USER` | Delete User | Tool to delete a user. Use after confirming the user exists to remove them permanently. | | `REPLY_GENERATE_ULID` | Generate ULID | Generate ULID | | `REPLY_GET_ALL_LISTS` | Get All Lists | Tool to retrieve all available people lists. Use when you need to list all lists in your Reply account. | | `REPLY_GET_BLACKLIST_ALL` | Get full blacklist of domains and emails | Tool to retrieve the full list of blacklisted domains and emails. Use after confirming updates to the blacklist when you need a complete view. | | `REPLY_GET_CAMPAIGN_SCHEDULES_ALL` | Get all campaign schedules | Retrieves all campaign schedules from Reply.io, including the default schedule and any user-created schedules. Each schedule contains timezone settings, daily timing configurations (mainTimings), and follow-up timings. Use this to view available schedules before assigning one to a campaign or to audit existing schedule configurations. | | `REPLY_GET_CAMPAIGNS_FOR_CONTACT` | Get Campaigns For Contact | Tool to retrieve campaigns a contact belongs to by contact ID. Use when you need to list all sequences (campaigns) associated with a specific contact. | | `REPLY_GET_CONTACTS_IN_LIST_BY_ID` | Get Contacts in List by ID | Tool to retrieve contacts in a specific personal list. Use after obtaining the list ID when you need a paginated set of contacts for that list. | | `REPLY_GET_LIST_BY_ID` | Get List by ID | Tool to return a specific people list by its ID. Use after you know the list ID and need its details. | | `REPLY_GET_TEMPLATES_LIST` | Get templates list | Retrieves all email templates from Reply.io, including user-created, team-shared, organization-wide, and community templates. Use this to browse available templates before sending emails or creating campaigns. No parameters required - returns all accessible templates for the authenticated user. | | `REPLY_LIST_CAMPAIGNS` | List Campaigns | Tool to list all campaigns (sequences). Use when you need a paginated list of campaigns. | | `REPLY_LIST_CONTACTS_BASIC` | List Contacts Basic | Tool to list contacts. Use when verifying API access and gathering contact IDs. | | `REPLY_LIST_EMAIL_ACCOUNTS` | Reply.io List Email Accounts | Tool to list all email accounts. Use when you need to retrieve email accounts page by page. | | `REPLY_MARK_CONTACT_AS_FINISHED` | Mark Contact As Finished | Marks a contact (by email) or all contacts under a domain as finished in all Reply.io campaigns. Use this tool to stop outreach for contacts who have been successfully engaged or should no longer receive campaign messages. - When using 'email': The specific contact must exist and be enrolled in at least one campaign. - When using 'domain': Marks all contacts with that email domain as finished (succeeds even if no contacts match). Note: Provide exactly one of 'email' or 'domain', not both. | | `REPLY_MARK_CONTACT_AS_REPLIED` | Mark Contact as Replied | Tool to mark a contact as replied in all campaigns by email or domain. Use after confirming the contact has responded. | | `REPLY_MOVE_CONTACTS_TO_LISTS` | Move Contacts to Lists | Tool to move one or more contacts to specified lists. Use when reorganizing contacts across lists after verifying contact and list IDs. | | `REPLY_REMOVE_DOMAIN_FROM_BLACKLIST` | Remove Domain from Blacklist | Tool to remove the specified domain from the blacklist. Use when you need to allow sending to that domain again. | | `REPLY_SEARCH_CONTACTS` | Search Contacts by Email | Tool to search contacts by email. Use when you need to find existing contact IDs for update tests. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Reply MCP server is an implementation of the Model Context Protocol that connects your AI agent to Reply. It provides structured and secure access so your agent can perform Reply 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 you begin, make sure you have: - Node.js and npm installed - A Composio account with API key - An OpenAI API key ### 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'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](https://dashboard.composio.dev?utm_source=toolkits&utm_medium=framework_docs). - Navigate to your API settings and generate a new API key. - Store this key securely as you'll need it for authentication. ### 2. Install required dependencies First, install the necessary packages for your project. What you're installing: - @ai-sdk/openai: Vercel AI SDK's OpenAI provider - @ai-sdk/mcp: MCP client for Vercel AI SDK - @composio/core: Composio SDK for tool integration - ai: Core Vercel AI SDK - dotenv: Environment variable management ```bash npm install @ai-sdk/openai @ai-sdk/mcp @composio/core ai dotenv ``` ### 3. Set up environment variables Create a .env file in your project root. What's needed: - OPENAI_API_KEY: Your OpenAI API key for GPT model access - COMPOSIO_API_KEY: Your Composio API key for tool access - COMPOSIO_USER_ID: A unique identifier for the user session ```bash OPENAI_API_KEY=your_openai_api_key_here COMPOSIO_API_KEY=your_composio_api_key_here COMPOSIO_USER_ID=your_user_id_here ``` ### 4. Import required modules and validate environment What's happening: - We're importing all necessary libraries including Vercel AI SDK's OpenAI provider and Composio - The dotenv/config import automatically loads environment variables - The MCP client import enables connection to Composio's tool server ```typescript import "dotenv/config"; import { openai } from "@ai-sdk/openai"; import { Composio } from "@composio/core"; import * as readline from "readline"; import { streamText, type ModelMessage, stepCountIs } from "ai"; import { createMCPClient } from "@ai-sdk/mcp"; const composioAPIKey = process.env.COMPOSIO_API_KEY; const composioUserID = process.env.COMPOSIO_USER_ID; if (!process.env.OPENAI_API_KEY) 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, }); ``` ### 5. Create Tool Router session and initialize MCP client What's happening: - We're creating a Tool Router session that gives your agent access to Reply tools - The create method takes the user ID and specifies which toolkits should be available - The returned mcp object contains the URL and authentication headers needed to connect to the MCP server - This session provides access to all Reply-related tools through the MCP protocol ```typescript async function main() { // Create a tool router session for the user const session = await composio.create(composioUserID!, { toolkits: ["reply"], }); const mcpUrl = session.mcp.url; ``` ### 6. Connect to MCP server and retrieve tools What's happening: - We're creating an MCP client that connects to our Composio Tool Router session via HTTP - The mcp.url provides the endpoint, and mcp.headers contains authentication credentials - The type: "http" is important - Composio requires HTTP transport - tools() retrieves all available Reply tools that the agent can use ```typescript const mcpClient = await createMCPClient({ transport: { type: "http", url: mcpUrl, headers: session.mcp.headers, // Authentication headers for the Composio MCP server }, }); const tools = await mcpClient.tools(); ``` ### 7. Initialize conversation and CLI interface What's happening: - We initialize an empty messages array to maintain conversation history - A readline interface is created to accept user input from the command line - Instructions are displayed to guide the user on how to interact with the agent ```typescript let messages: ModelMessage[] = []; console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n"); console.log( "Ask any questions related to reply, like summarize my last 5 emails, send an email, etc... :)))\n", ); const rl = readline.createInterface({ input: process.stdin, output: process.stdout, prompt: "> ", }); rl.prompt(); ``` ### 8. Handle user input and stream responses with real-time tool feedback What's happening: - We use streamText instead of generateText to stream responses in real-time - toolChoice: "auto" allows the model to decide when to use Reply tools - stopWhen: stepCountIs(10) allows up to 10 steps for complex multi-tool operations - onStepFinish callback displays which tools are being used in real-time - We iterate through the text stream to create a typewriter effect as the agent responds - The complete response is added to conversation history to maintain context - Errors are caught and displayed with helpful retry suggestions ```typescript 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({ role: "user", content: trimmedInput }); console.log("\nAgent is thinking...\n"); try { const stream = streamText({ model: openai("gpt-5"), messages, tools, toolChoice: "auto", stopWhen: stepCountIs(10), onStepFinish: (step) => { for (const toolCall of step.toolCalls) { console.log(`[Using tool: ${toolCall.toolName}]`); } if (step.toolCalls.length > 0) { console.log(""); // Add space after tool calls } }, }); for await (const chunk of stream.textStream) { process.stdout.write(chunk); } console.log("\n\n---\n"); // Get final result for message history const response = await stream.response; if (response?.messages?.length) { messages.push(...response.messages); } } catch (error) { console.error("\nAn error occurred while talking to the agent:"); console.error(error); console.log( "\nYou can try again or restart the app if it keeps happening.\n", ); } finally { rl.prompt(); } }); rl.on("close", async () => { await mcpClient.close(); console.log("\n👋 Session ended."); 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 { Composio } from "@composio/core"; import * as readline from "readline"; import { streamText, type ModelMessage, stepCountIs } from "ai"; import { createMCPClient } from "@ai-sdk/mcp"; const composioAPIKey = process.env.COMPOSIO_API_KEY; const composioUserID = process.env.COMPOSIO_USER_ID; if (!process.env.OPENAI_API_KEY) 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, }); async function main() { // Create a tool router session for the user const session = await composio.create(composioUserID!, { toolkits: ["reply"], }); const mcpUrl = session.mcp.url; const mcpClient = await createMCPClient({ transport: { type: "http", url: mcpUrl, headers: session.mcp.headers, // Authentication headers for the Composio MCP server }, }); const tools = await mcpClient.tools(); let messages: ModelMessage[] = []; console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n"); console.log( "Ask any questions related to reply, like summarize my last 5 emails, send an email, etc... :)))\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({ role: "user", content: trimmedInput }); console.log("\nAgent is thinking...\n"); try { const stream = streamText({ model: openai("gpt-5"), messages, tools, toolChoice: "auto", stopWhen: stepCountIs(10), onStepFinish: (step) => { for (const toolCall of step.toolCalls) { console.log(`[Using tool: ${toolCall.toolName}]`); } if (step.toolCalls.length > 0) { console.log(""); // Add space after tool calls } }, }); for await (const chunk of stream.textStream) { process.stdout.write(chunk); } console.log("\n\n---\n"); // Get final result for message history const response = await stream.response; if (response?.messages?.length) { messages.push(...response.messages); } } catch (error) { console.error("\nAn error occurred while talking to the agent:"); console.error(error); console.log( "\nYou can try again or restart the app if it keeps happening.\n", ); } finally { rl.prompt(); } }); rl.on("close", async () => { await mcpClient.close(); console.log("\n👋 Session ended."); process.exit(0); }); } main().catch((err) => { console.error("Fatal error:", err); process.exit(1); }); ``` ## Conclusion You've successfully built a Reply agent using the Vercel AI SDK with streaming capabilities! This implementation provides a powerful foundation for building AI applications with natural language interfaces and real-time feedback. Key features of this implementation: - Real-time streaming responses for a better user experience with typewriter effect - Live tool execution feedback showing which tools are being used as the agent works - Dynamic tool loading through Composio's Tool Router with secure authentication - Multi-step tool execution with configurable step limits (up to 10 steps) - Comprehensive error handling for robust agent execution - Conversation history maintenance for context-aware responses You can extend this further by adding custom error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows. ## How to build Reply MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/reply/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/reply/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/reply/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/reply/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/reply/framework/codex) - [OpenClaw](https://composio.dev/toolkits/reply/framework/openclaw) - [Hermes](https://composio.dev/toolkits/reply/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/reply/framework/cli) - [Google ADK](https://composio.dev/toolkits/reply/framework/google-adk) - [LangChain](https://composio.dev/toolkits/reply/framework/langchain) - [Mastra AI](https://composio.dev/toolkits/reply/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/reply/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/reply/framework/crew-ai) ## Related Toolkits - [Aeroleads](https://composio.dev/toolkits/aeroleads) - Aeroleads is a B2B lead generation platform for finding business emails and phone numbers. Grow your sales pipeline faster with powerful prospecting tools. - [Autobound](https://composio.dev/toolkits/autobound) - Autobound is an AI-powered sales engagement platform that crafts hyper-personalized outreach and insights. It helps sales teams boost response rates and close more deals through tailored content and recommendations. - [Better proposals](https://composio.dev/toolkits/better_proposals) - Better Proposals is a web-based tool for crafting and sending professional proposals. It helps teams impress clients and close deals faster with slick, easy-to-use templates. - [Bidsketch](https://composio.dev/toolkits/bidsketch) - Bidsketch is a proposal software that helps businesses create professional proposals quickly and efficiently. It streamlines the proposal process, saving time while boosting client win rates. - [Bolna](https://composio.dev/toolkits/bolna) - Bolna is an AI platform for building conversational voice agents. It helps businesses automate support and streamline interactions through natural, voice-powered conversations. - [Botsonic](https://composio.dev/toolkits/botsonic) - Botsonic is a no-code AI chatbot builder for easily creating and deploying chatbots to your website. It empowers businesses to offer conversational experiences without writing code. - [Botstar](https://composio.dev/toolkits/botstar) - BotStar is a comprehensive chatbot platform for designing, developing, and training chatbots visually on Messenger and websites. It helps businesses automate conversations and customer interactions without coding. - [Callerapi](https://composio.dev/toolkits/callerapi) - CallerAPI is a white-label caller identification platform for branded caller ID and fraud prevention. It helps businesses boost customer trust while stopping spam, fraud, and robocalls. - [Callingly](https://composio.dev/toolkits/callingly) - Callingly is a lead response management platform that automates immediate call and text follow-ups with new leads. It helps sales teams boost response speed and close more deals by connecting seamlessly with CRMs and lead sources. - [Callpage](https://composio.dev/toolkits/callpage) - Callpage is a lead capture platform that lets businesses instantly connect with website visitors via callback. It boosts lead generation and increases your sales conversion rates. - [Clearout](https://composio.dev/toolkits/clearout) - Clearout is an AI-powered service for verifying, finding, and enriching email addresses. It boosts deliverability and helps you discover high-quality leads effortlessly. - [Clientary](https://composio.dev/toolkits/clientary) - Clientary is a platform for managing clients, invoices, projects, proposals, and more. It streamlines client work and saves you serious admin time. - [Convolo ai](https://composio.dev/toolkits/convolo_ai) - Convolo ai is an AI-powered communications platform for sales teams. It accelerates lead response and improves conversion rates by automating calls and integrating workflows. - [Delighted](https://composio.dev/toolkits/delighted) - Delighted is a customer feedback platform based on the Net Promoter System®. It helps you quickly gather, track, and act on customer sentiment. - [Emelia](https://composio.dev/toolkits/emelia) - Emelia is an all-in-one B2B prospecting platform for cold-email, LinkedIn outreach, and prospect research. It streamlines outbound campaigns so you can find, engage, and warm up leads faster. - [Findymail](https://composio.dev/toolkits/findymail) - Findymail is a B2B data provider offering verified email and phone contacts for sales prospecting. Enhance outreach with automated exports, email verification, and CRM enrichment. - [Freshdesk](https://composio.dev/toolkits/freshdesk) - Freshdesk is customer support software with ticketing and automation tools. It helps teams streamline helpdesk operations for faster, better customer support. - [Fullenrich](https://composio.dev/toolkits/fullenrich) - FullEnrich is a B2B contact enrichment platform that aggregates emails and phone numbers from 15+ data vendors. Instantly find and verify lead contact data to boost your outreach. - [Gatherup](https://composio.dev/toolkits/gatherup) - GatherUp is a customer feedback and online review management platform. It helps businesses boost their reputation by streamlining how they collect and manage customer feedback. - [Getprospect](https://composio.dev/toolkits/getprospect) - Getprospect is a business email discovery tool with LinkedIn integration. Use it to quickly find and verify professional email addresses. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Reply MCP? With a standalone Reply MCP server, the agents and LLMs can only access a fixed set of Reply tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Reply and many other apps based on the task at hand, all through a single MCP endpoint. ### Can I use Tool Router MCP with Vercel AI SDK v6? Yes, you can. Vercel AI SDK v6 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 Reply tools. ### Can I manage the permissions and scopes for Reply while using Tool Router? Yes, absolutely. You can configure which Reply 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 Reply data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)