# How to integrate Hunter MCP with Vercel AI SDK v6 ```json { "title": "How to integrate Hunter MCP with Vercel AI SDK v6", "toolkit": "Hunter", "toolkit_slug": "hunter", "framework": "Vercel AI SDK", "framework_slug": "ai-sdk", "url": "https://composio.dev/toolkits/hunter/framework/ai-sdk", "markdown_url": "https://composio.dev/toolkits/hunter/framework/ai-sdk.md", "updated_at": "2026-05-12T10:15:24.853Z" } ``` ## Introduction This guide walks you through connecting Hunter to Vercel AI SDK v6 using the Composio tool router. By the end, you'll have a working Hunter agent that can find all public emails at acme.com, enrich company details for tesla.com, create new lead with given info through natural language commands. This guide will help you understand how to give your Vercel AI SDK agent real control over a Hunter account through Composio's Hunter MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved. ## Also integrate Hunter with - [OpenAI Agents SDK](https://composio.dev/toolkits/hunter/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/hunter/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/hunter/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/hunter/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/hunter/framework/codex) - [OpenClaw](https://composio.dev/toolkits/hunter/framework/openclaw) - [Hermes](https://composio.dev/toolkits/hunter/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/hunter/framework/cli) - [Google ADK](https://composio.dev/toolkits/hunter/framework/google-adk) - [LangChain](https://composio.dev/toolkits/hunter/framework/langchain) - [Mastra AI](https://composio.dev/toolkits/hunter/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/hunter/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/hunter/framework/crew-ai) ## TL;DR Here's what you'll learn: - How to set up and configure a Vercel AI SDK agent with Hunter integration - Using Composio's Tool Router to dynamically load and access Hunter 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 Hunter MCP server, and what's possible with it? The Hunter MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Hunter account. It provides structured and secure access to your lead generation and enrichment tools, so your agent can perform actions like finding emails, enriching company data, managing leads, and organizing leads lists on your behalf. - Email discovery and search: Instantly ask your agent to find all public email addresses for a given company or domain, complete with metadata to fuel your outreach and marketing campaigns. - Smart lead creation and management: Let your agent add new leads, update lead details, or delete outdated entries to keep your Hunter account organized and up-to-date. - Company and contact enrichment: Have the agent fetch detailed company profiles or use the Email Finder to infer the best contact email for a specific person at a target company. - Leads list organization: Direct your agent to create, update, or remove custom leads lists—making it easy to segment prospects for personalized marketing or sales workflows. - Custom attribute management: Empower your agent to create or delete custom lead attributes, tailoring your CRM data fields to match your unique business needs. ## Supported Tools | Tool slug | Name | Description | |---|---|---| | `HUNTER_ACCOUNT_INFORMATION` | Account Information | Tool to retrieve information about your Hunter account. Use when you need to check your plan details and usage limits after confirming credentials. Returns `searches.available` and `verifications.available` fields among others; check these before bulk operations to avoid quota exhaustion. | | `HUNTER_COMBINED_ENRICHMENT` | Combined Enrichment | Tool to find both person and company information from an email address or LinkedIn handle in a single request. Use when you need complete professional profile enrichment including employment and company details. | | `HUNTER_COMPANY_ENRICHMENT` | Company Enrichment | Tool to get enrichment information for a company by its domain. Use when you need full company details (industry, description, location, metrics) from Hunter. | | `HUNTER_CREATE_CUSTOM_ATTRIBUTE` | Create custom lead attribute | Tool to create a new custom lead attribute in your account. Use after deciding on the attribute label. | | `HUNTER_CREATE_LEAD` | Create Lead | Tool to create a new lead. Use after gathering all prospect details to save them to your Hunter account. | | `HUNTER_CREATE_LEADS_LIST` | Create Leads List | Tool to create a new leads list. Use when you need to organize leads into a custom list before adding leads. | | `HUNTER_DELETE_CUSTOM_ATTRIBUTE` | Delete Custom Attribute | Tool to delete an existing custom attribute. Use after confirming the attribute ID to be removed. | | `HUNTER_DELETE_LEAD` | Delete Lead | Tool to delete a lead. Use after confirming the lead's ID to remove it from your Hunter.io account. | | `HUNTER_DELETE_LEADS_LIST` | Delete Leads List | Tool to delete a leads list by its ID. Use after confirming the leads list ID to remove it from your Hunter.io account. | | `HUNTER_DISCOVER_COMPANIES` | Discover Companies | Tool to search and retrieve companies matching specified criteria using filters or natural language queries. Use when you need to discover companies from Hunter's B2B dataset based on industry, location, size, or other characteristics. | | `HUNTER_DOMAIN_SEARCH` | Domain Search | Tool to search all email addresses for a given domain or company. Use when you need public emails and metadata for outreach or enrichment. Rate-limited; HTTP 429 returned on excess requests — honor the Retry-After header. | | `HUNTER_EMAIL_COUNT` | Email Count | Tool to get the total number of email addresses Hunter has for a domain or company with breakdowns by type, department, and seniority. Use when you need email volume statistics without consuming API credits (this call is free). | | `HUNTER_EMAIL_FINDER` | Email Finder | Tool to find the most likely email address for a person at a domain or company. Use when you have a person's name and a domain or company and need to infer their email. Results include a confidence score and status; treat emails with status 'accept_all' or 'risky' as lower reliability. Each call consumes API credits — avoid re-enriching the same contact. | | `HUNTER_EMAIL_VERIFIER` | Email Verifier | Tool to verify the deliverability of an email address. Use when you need to ensure an address is valid and reachable. Response may include statuses `accept_all` or `risky`, indicating uncertain deliverability; do not treat these as fully valid without explicit review. For bulk verification, honor `Retry-After` headers on HTTP 429 responses and use exponential backoff. | | `HUNTER_GET_CUSTOM_ATTRIBUTE` | Get Custom Attribute | Tool to retrieve details of a specific custom attribute. Use when you need the label and slug for an attribute ID. | | `HUNTER_GET_LEAD` | Get Lead | Tool to retrieve details of a specific lead by ID. Use after confirming the lead's ID to fetch its full record. | | `HUNTER_GET_LEADS_LIST` | Get Leads List | Tool to retrieve details of a specific leads list by ID. Use when you need to inspect the contents of an existing leads list. | | `HUNTER_LIST_CAMPAIGNS` | List Campaigns | Tool to get all email campaigns in your Hunter account. Campaigns are returned in reverse-chronological order by creation date. Use when you need to retrieve and filter campaigns by status (started/archived) with pagination support. | | `HUNTER_LIST_CUSTOM_ATTRIBUTES` | List Custom Attributes | Tool to list all custom lead attributes in your account. Use when you need to retrieve your account's custom lead attributes after authenticating. | | `HUNTER_LIST_LEADS` | List Leads | Tool to list all leads saved in your account with optional filters. Use when you need to retrieve leads with specific criteria after confirming your API key. | | `HUNTER_LIST_LEADS_LISTS` | List Leads Lists | Tool to list all leads lists in your account. Use when you need to retrieve and paginate through your leads lists. | | `HUNTER_PEOPLE_ENRICHMENT` | People Enrichment | Tool to find all information associated with an email address or LinkedIn profile including name, location, job title and social handles. Use when you need to enrich contact data with additional personal and professional details. | | `HUNTER_UPDATE_CUSTOM_ATTRIBUTE` | Update Custom Attribute | Tool to update an existing custom attribute's label. Use when renaming a custom attribute after creation. | | `HUNTER_UPDATE_LEAD` | Update Lead | Tool to update details of an existing lead by ID. Use when you need to modify saved lead attributes after creation. | | `HUNTER_UPDATE_LEADS_LIST` | Update Leads List | Tool to update the name of a specific leads list. Use when renaming an existing leads list. | | `HUNTER_UPSERT_LEAD` | Upsert Lead | Tool to create or update a lead by email in one call. Use when you want to ensure a lead exists with the provided information without checking its existence first. | ## Supported Triggers None listed. ## Creating MCP Server - Stand-alone vs Composio SDK The Hunter MCP server is an implementation of the Model Context Protocol that connects your AI agent to Hunter. It provides structured and secure access so your agent can perform Hunter 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 Hunter 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 Hunter-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: ["hunter"], }); 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 Hunter 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 hunter, 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 Hunter 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: ["hunter"], }); 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 hunter, 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 Hunter 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 Hunter MCP Agent with another framework - [OpenAI Agents SDK](https://composio.dev/toolkits/hunter/framework/open-ai-agents-sdk) - [Claude Agent SDK](https://composio.dev/toolkits/hunter/framework/claude-agents-sdk) - [Claude Code](https://composio.dev/toolkits/hunter/framework/claude-code) - [Claude Cowork](https://composio.dev/toolkits/hunter/framework/claude-cowork) - [Codex](https://composio.dev/toolkits/hunter/framework/codex) - [OpenClaw](https://composio.dev/toolkits/hunter/framework/openclaw) - [Hermes](https://composio.dev/toolkits/hunter/framework/hermes-agent) - [CLI](https://composio.dev/toolkits/hunter/framework/cli) - [Google ADK](https://composio.dev/toolkits/hunter/framework/google-adk) - [LangChain](https://composio.dev/toolkits/hunter/framework/langchain) - [Mastra AI](https://composio.dev/toolkits/hunter/framework/mastra-ai) - [LlamaIndex](https://composio.dev/toolkits/hunter/framework/llama-index) - [CrewAI](https://composio.dev/toolkits/hunter/framework/crew-ai) ## Related Toolkits - [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. - [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. - [Beamer](https://composio.dev/toolkits/beamer) - Beamer is a news and changelog platform for in-app announcements and feature updates. It helps companies boost user engagement by sharing news where users are most active. - [Benchmark email](https://composio.dev/toolkits/benchmark_email) - Benchmark Email is a platform for creating, sending, and tracking email campaigns. It's built to help you engage audiences and analyze results—all in one place. - [Bigmailer](https://composio.dev/toolkits/bigmailer) - BigMailer is an email marketing platform for managing multiple brands with white-labeling and automation. It helps teams streamline campaigns and simplify integration with Amazon SES. - [Brandfetch](https://composio.dev/toolkits/brandfetch) - Brandfetch is an API that delivers company logos, colors, and visual branding assets. It helps marketers and developers keep brand visuals consistent everywhere. - [Brevo](https://composio.dev/toolkits/brevo) - Brevo is an all-in-one email and SMS marketing platform for transactional messaging, automation, and CRM. It helps businesses engage customers and streamline communications through powerful campaign tools. - [Campayn](https://composio.dev/toolkits/campayn) - Campayn is an email marketing platform for creating, sending, and managing campaigns. It helps businesses engage contacts and grow audiences with easy-to-use tools. - [Cardly](https://composio.dev/toolkits/cardly) - Cardly is a platform for creating and sending personalized direct mail to customers. It helps businesses break through the digital clutter by getting real engagement via physical mailboxes. - [ClickSend](https://composio.dev/toolkits/clicksend) - ClickSend is a cloud-based SMS and email marketing platform for businesses. It streamlines communication by enabling quick message delivery and contact management. - [Crustdata](https://composio.dev/toolkits/crustdata) - CrustData is an AI-powered data intelligence platform for real-time company and people data. It helps B2B sales teams, AI SDRs, and investors react to live business signals. - [Curated](https://composio.dev/toolkits/curated) - Curated is a platform for collecting, curating, and publishing newsletters. It streamlines content aggregation and distribution for creators and teams. - [Customerio](https://composio.dev/toolkits/customerio) - Customer.io is a customer engagement platform for targeted messaging across email, SMS, and push. Easily automate, segment, and track communications with your audience. - [Cutt ly](https://composio.dev/toolkits/cutt_ly) - Cutt.ly is a URL shortening service for managing and analyzing links. Streamline your workflows with quick, trackable, and branded short URLs. - [Demio](https://composio.dev/toolkits/demio) - Demio is webinar software built for marketers, offering both live and automated sessions with interactive features. It helps teams engage audiences and optimize lead generation through detailed analytics. ## Frequently Asked Questions ### What are the differences in Tool Router MCP and Hunter MCP? With a standalone Hunter MCP server, the agents and LLMs can only access a fixed set of Hunter tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Hunter 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 Hunter tools. ### Can I manage the permissions and scopes for Hunter while using Tool Router? Yes, absolutely. You can configure which Hunter 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 Hunter data and credentials are handled as safely as possible. --- [See all toolkits](https://composio.dev/toolkits) · [Composio docs](https://docs.composio.dev/llms.txt)