How to integrate Hunter MCP with Claude Agent SDK

This guide walks you through connecting Hunter to the Claude Agent SDK 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 Claude Agent 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.

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Hunter

Api Key

Hunter is an email marketing platform for lead generation and contact data enrichment. It helps you quickly find and verify professional email addresses to boost outreach.

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Introduction

This guide will help you understand how to give your Claude Agent 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 Claude Code Claude Cowork Codex OpenClaw Hermes CLI Google ADK LangChain Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

Get and set up your Claude/Anthropic and Composio API keys
Install the necessary dependencies
Initialize Composio and create a Tool Router session for Hunter
Configure an AI agent that can use Hunter as a tool
Run a live chat session where you can ask the agent to perform Hunter operations

What is Claude Agent SDK?

The Claude Agent SDK is Anthropic's official framework for building AI agents powered by Claude. It provides a streamlined interface for creating agents with MCP tool support and conversation management.

Key features include:

Native MCP Support: Built-in support for Model Context Protocol servers
Permission Modes: Control tool execution permissions
Streaming Responses: Real-time response streaming for interactive applications
Context Manager: Clean async context management for sessions

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.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step09 STEPS

Prerequisites

Before starting, make sure you have:

Composio API Key and Claude/Anthropic API Key
Primary know-how of Claude Agents SDK
A Hunter account
Some knowledge of Python

Getting API Keys for Claude/Anthropic and Composio

Claude/Anthropic API Key

Go to the Anthropic Console and create an API key. You'll need credits to use the models.
Keep the API key safe.

Composio API Key

Log in to the Composio dashboard.
Navigate to your API settings and generate a new API key.
Store this key securely as you'll need it for authentication.

Install dependencies

npm install @anthropic-ai/claude-agent-sdk @composio/core dotenv

Install the Composio SDK and the Claude Agents SDK.

What's happening:

@composio/core provides Composio integration for Anthropic
@anthropic-ai/claude-agent-sdk is the core agent framework
dotenv/config loads environment variables

Set up environment variables

bash

COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
ANTHROPIC_API_KEY=your_anthropic_api_key_here

Create a .env file in your project root.

What's happening:

COMPOSIO_API_KEY authenticates with Composio
USER_ID identifies the user for session management
ANTHROPIC_API_KEY authenticates with Anthropic/Claude

Import dependencies

import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

dotenv.config();

What's happening:

We're importing all necessary libraries including the Claude Agent SDK and Composio
The dotenv.config() function loads environment variables from your .env file
This setup prepares the foundation for connecting Claude with Hunter functionality

Create a Composio instance and Tool Router session

async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

  const composio = new Composio({ apiKey: COMPOSIO_API_KEY });

  // Create Tool Router session for Hunter
  const session = await composio.create(USER_ID, {
    toolkits: ['hunter'],
  });
  const mcpUrl = session?.mcp.url;

What's happening:

The function checks for the required COMPOSIO_API_KEY environment variable
We're creating a Composio instance using our API key
The create method creates a Tool Router session for Hunter
The returned url is the MCP server URL that your agent will use

Configure Claude Agent with MCP

const options: Options = {
  permissionMode: 'bypassPermissions',
  mcpServers: {
    composio: {
      type: 'http',
      url: mcpUrl,
      headers: { 'x-api-key': COMPOSIO_API_KEY }
    }
  },
  systemPrompt: 'You are a helpful assistant with access to Hunter tools via Composio.',
  maxTurns: 10,
};

What's happening:

We're configuring the Claude Agent options with the MCP server URL
permissionMode: 'bypassPermissions' allows the agent to execute operations without asking for permission each time
The system prompt instructs the agent that it has access to Hunter
maxTurns: 10 limits the conversation length to prevent excessive API usage

Create client and start chat loop

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

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}

What's happening:

The readline interface is created to handle user input and output
The query function is used to send the user's input to the agent
The chat loop continues until the user types 'exit' or 'quit'

Run the application

try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}

What's happening:

The chat function is the entry point for the application
The try-catch block is used to handle any errors that occur

Complete Code

Here's the complete code to get you started with Hunter and Claude Agent SDK:

import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

  const composio = new Composio({ apiKey: COMPOSIO_API_KEY });
  const session = await composio.create(USER_ID, {
    toolkits: ['hunter']
  });
  const mcp_url = session?.mcp.url;

  const options: Options = {
    permissionMode: 'bypassPermissions',
    mcpServers: {
      composio: {
        type: 'http',
        url: mcp_url,
        headers: { 'x-api-key': COMPOSIO_API_KEY }
      }
    },
    systemPrompt: 'You are a helpful assistant with access to Hunter tools via Composio.',
    maxTurns: 10,
  };

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

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}

try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}

Conclusion

You've successfully built a Claude Agent SDK agent that can interact with Hunter through Composio's Tool Router.

Key features:

Native MCP support through Claude's agent framework
Streaming responses for real-time interaction
Permission bypass for smooth automated workflows

You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.

TOOLS

Supported Tools

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

Account Information

Tool to retrieve information about your Hunter account.

Combined Enrichment

Tool to find both person and company information from an email address or LinkedIn handle in a single request.

Company Enrichment

Tool to get enrichment information for a company by its domain.

Create custom lead attribute

Tool to create a new custom lead attribute in your account.

Create Lead

Tool to create a new lead.

Create Leads List

Tool to create a new leads list.

Delete Custom Attribute

Tool to delete an existing custom attribute.

Delete Lead

Tool to delete a lead.

Delete Leads List

Tool to delete a leads list by its ID.

Discover Companies

Tool to search and retrieve companies matching specified criteria using filters or natural language queries.

Domain Search

Tool to search all email addresses for a given domain or company.

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.

Email Finder

Tool to find the most likely email address for a person at a domain or company.

Email Verifier

Tool to verify the deliverability of an email address.

Get Custom Attribute

Tool to retrieve details of a specific custom attribute.

Get Lead

Tool to retrieve details of a specific lead by ID.

Get Leads List

Tool to retrieve details of a specific leads list by ID.

List Campaigns

Tool to get all email campaigns in your Hunter account.

List Custom Attributes

Tool to list all custom lead attributes in your account.

List Leads

Tool to list all leads saved in your account with optional filters.

List Leads Lists

Tool to list all leads lists in your account.

People Enrichment

Tool to find all information associated with an email address or LinkedIn profile including name, location, job title and social handles.

Update Custom Attribute

Tool to update an existing custom attribute's label.

Update Lead

Tool to update details of an existing lead by ID.

Update Leads List

Tool to update the name of a specific leads list.

Upsert Lead

Tool to create or update a lead by email in one call.

FRAMEWORKS

How to build Hunter MCP Agent with another framework

OpenAI Agents SDK

Use Hunter MCP with OpenAI Agents SDK

Claude Code

Use Hunter MCP with Claude Code

Claude Cowork

Use Hunter MCP with Claude Cowork

Codex

Use Hunter MCP with Codex

OpenClaw

Use Hunter MCP with OpenClaw

Hermes

Use Hunter MCP with Hermes

CLI

Use Hunter MCP with CLI

Google ADK

Use Hunter MCP with Google ADK

LangChain

Use Hunter MCP with LangChain

Vercel AI SDK

Use Hunter MCP with Vercel AI SDK

Mastra AI

Use Hunter MCP with Mastra AI

LlamaIndex

Use Hunter MCP with LlamaIndex

CrewAI

Use Hunter MCP with CrewAI

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Facebook

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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

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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.

FAQ

Frequently asked questions

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.

Yes, you can. Claude Agent SDK 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.

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.

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.

Start with Hunter.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Hunter tool your agent needs.Free to start.

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Customer stories

Teams ship real agents on Composio

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Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati

Co-founder, Slashy

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

Abhi Arya

Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

Nirman Dave

CEO, Zams

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

Ryan Yu

Founder, Extra Thursday

Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

Tomisin Jenrola

Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Jerome Leclanche

Co-Founder, Ingram Technologies

How to integrate Hunter MCP with Claude Agent SDK

Connect Hunter without auth hassles

Introduction

Also integrate Hunter with

TL;DR

What is Claude Agent SDK?

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

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

How the Composio SDK works

Step-by-step Guide

Prerequisites

Getting API Keys for Claude/Anthropic and Composio

Install dependencies

Set up environment variables

Import dependencies

Create a Composio instance and Tool Router session

Configure Claude Agent with MCP

Create client and start chat loop

Run the application

Complete Code

Conclusion

Supported Tools

How to build Hunter MCP Agent with another framework

OpenAI Agents SDK

Claude Code

Claude Cowork

Codex

OpenClaw

Hermes

CLI

Google ADK

LangChain

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

Explore Other Toolkits

Reddit

Facebook

Linkedin

Active campaign

Frequently asked questions

What are the differences in Tool Router MCP and Hunter MCP?+

Can I use Tool Router MCP with Claude Agent SDK?+

Can I manage the permissions and scopes for Hunter while using Tool Router?+

How safe is my data with Composio Tool Router?+

Start with Hunter.It takes 30 seconds.

Teams ship real agents on Composio