How to integrate RedCircle API MCP with LangChain

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Introduction

This guide walks you through connecting RedCircle API to LangChain using the Composio tool router. By the end, you'll have a working RedCircle API agent that can search target for nintendo switch bundles, get reviews for dyson vacuums at target, list top-rated target products in electronics through natural language commands.

This guide will help you understand how to give your LangChain agent real control over a RedCircle API account through Composio's RedCircle API MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Connect your RedCircle API project to Composio
  • Create a Tool Router MCP session for RedCircle API
  • Initialize an MCP client and retrieve RedCircle API tools
  • Build a LangChain agent that can interact with RedCircle API
  • Set up an interactive chat interface for testing

What is LangChain?

LangChain is a framework for developing applications powered by language models. It provides tools and abstractions for building agents that can reason, use tools, and maintain conversation context.

Key features include:

  • Agent Framework: Build agents that can use tools and make decisions
  • MCP Integration: Connect to external services through Model Context Protocol adapters
  • Memory Management: Maintain conversation history across interactions
  • Multi-Provider Support: Works with OpenAI, Anthropic, and other LLM providers

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

The RedCircle API MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your RedCircle API account. It provides structured and secure access so your agent can perform RedCircle API operations on your behalf.

Supported Tools & Triggers

Tools
Add ZipcodesTool to add zipcodes to your RedCircle API account for geolocation targeting.
Clear Collection RequestsTool to remove all requests from a specified collection.
Create CollectionTool to create a new collection for running up to 15,000 requests on a schedule.
Create DestinationTool to create a new destination for uploading Collection Result Sets to cloud storage.
Create RequestsTool to add up to 1,000 requests to an existing collection.
Delete CollectionTool to remove a collection from the system by ID.
Delete DestinationTool to remove a destination from your RedCircle API account.
Delete Request from CollectionTool to remove an individual request from a collection.
Delete Requests In BulkTool to delete multiple requests from a collection in bulk.
Delete ZipcodesTool to remove zipcodes from your RedCircle API account.
Get Account InformationTool to retrieve account information, usage metrics, and platform status.
Get CollectionTool to retrieve complete information about a specific collection.
Get Requests CSV LinksTool to retrieve CSV download links for all requests in a collection.
Get Requests JSON LinksTool to retrieve download links for all requests in a collection in JSON format.
Get Result Set CSVTool to retrieve a result set in CSV format with optional field filtering.
Get Result Set JSONTool to retrieve a result set in JSON format with download links.
Get Result Set JSON LinesTool to retrieve a result set in JSON Lines format with download links.
Get Target Product DataTool to retrieve Target data in real-time including search results, product information, reviews, or category listings.
List CategoriesTool to retrieve all top-level (root) categories or filter results using optional parameters.
List CollectionsTool to retrieve all collections configured on your RedCircle API account with filtering and pagination.
List DestinationsTool to retrieve all destinations configured on your RedCircle API account with pagination and filtering.
List Error LogsTool to list all error logs on your RedCircle API account.
List Requests by PageTool to retrieve requests for a collection in paginated format.
List Result SetsTool to list all result sets for a collection.
List ZipcodesTool to retrieve all zipcodes associated with your account with optional filtering.
Resend WebhookTool to resend a previously configured webhook POST request for a result set.
Start CollectionTool to initiate execution of a RedCircle API collection.
Stop All CollectionsTool to halt all currently active collections on your account.
Stop CollectionTool to halt an active collection in queued or running state.
Update CollectionTool to update an existing collection's configuration and settings.
Update DestinationTool to modify an existing destination configuration on your RedCircle API account.
Update RequestTool to modify a request within a collection.

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

What is Tool Router?

Composio's Tool Router 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 Tool Router

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

How the Tool Router works

The Tool Router follows a three-phase workflow:

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

Step-by-step Guide

Prerequisites

Before starting this tutorial, make sure you have:
  • Python 3.10 or higher installed on your system
  • A Composio account with an API key
  • An OpenAI API key
  • Basic familiarity with Python and async programming

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard 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.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.

Install dependencies

pip install composio-langchain langchain-mcp-adapters langchain python-dotenv

Install the required packages for LangChain with MCP support.

What's happening:

  • composio-langchain provides Composio integration for LangChain
  • langchain-mcp-adapters enables MCP client connections
  • langchain is the core agent framework
  • python-dotenv loads environment variables

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_composio_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio's API
  • COMPOSIO_USER_ID identifies the user for session management
  • OPENAI_API_KEY enables access to OpenAI's language models

Import dependencies

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()
What's happening:
  • We're importing LangChain's MCP adapter and Composio SDK
  • The dotenv import loads environment variables from your .env file
  • This setup prepares the foundation for connecting LangChain with RedCircle API functionality through MCP

Initialize Composio client

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))

    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
What's happening:
  • We're loading the COMPOSIO_API_KEY from environment variables and validating it exists
  • Creating a Composio instance that will manage our connection to RedCircle API tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

# Create Tool Router session for RedCircle API
session = composio.create(
    user_id=os.getenv("COMPOSIO_USER_ID"),
    toolkits=['redcircle_api']
)

url = session.mcp.url
What's happening:
  • We're creating a Tool Router session that gives your agent access to RedCircle API tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
  • This approach allows the agent to dynamically load and use RedCircle API tools as needed

Configure the agent with the MCP URL

client = MultiServerMCPClient({
    "redcircle_api-agent": {
        "transport": "streamable_http",
        "url": session.mcp.url,
        "headers": {
            "x-api-key": os.getenv("COMPOSIO_API_KEY")
        }
    }
})

tools = await client.get_tools()

agent = create_agent("gpt-5", tools)
What's happening:
  • We're creating a MultiServerMCPClient that connects to our RedCircle API MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • get_tools() retrieves all available RedCircle API tools that the agent can use
  • We're creating a LangChain agent using the GPT-5 model

Set up interactive chat interface

conversation_history = []

print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
print("Ask any RedCircle API related question or task to the agent.\n")

while True:
    user_input = input("You: ").strip()

    if user_input.lower() in ['exit', 'quit', 'bye']:
        print("\nGoodbye!")
        break

    if not user_input:
        continue

    conversation_history.append({"role": "user", "content": user_input})
    print("\nAgent is thinking...\n")

    response = await agent.ainvoke({"messages": conversation_history})
    conversation_history = response['messages']
    final_response = response['messages'][-1].content
    print(f"Agent: {final_response}\n")
What's happening:
  • We initialize an empty conversation_history list to maintain context across interactions
  • A while loop continuously accepts user input from the command line
  • When a user types a message, it's added to the conversation history and sent to the agent
  • The agent processes the request using the ainvoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully

Run the application

if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • We call the main() function using asyncio.run() to start the application

Complete Code

Here's the complete code to get you started with RedCircle API and LangChain:

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
    
    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
    
    session = composio.create(
        user_id=os.getenv("COMPOSIO_USER_ID"),
        toolkits=['redcircle_api']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "redcircle_api-agent": {
            "transport": "streamable_http",
            "url": url,
            "headers": {
                "x-api-key": os.getenv("COMPOSIO_API_KEY")
            }
        }
    })
    
    tools = await client.get_tools()
  
    agent = create_agent("gpt-5", tools)
    
    conversation_history = []
    
    print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
    print("Ask any RedCircle API related question or task to the agent.\n")
    
    while True:
        user_input = input("You: ").strip()
        
        if user_input.lower() in ['exit', 'quit', 'bye']:
            print("\nGoodbye!")
            break
        
        if not user_input:
            continue
        
        conversation_history.append({"role": "user", "content": user_input})
        print("\nAgent is thinking...\n")
        
        response = await agent.ainvoke({"messages": conversation_history})
        conversation_history = response['messages']
        final_response = response['messages'][-1].content
        print(f"Agent: {final_response}\n")

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've successfully built a LangChain agent that can interact with RedCircle API through Composio's Tool Router.

Key features of this implementation:

  • Dynamic tool loading through Composio's Tool Router
  • Conversation history maintenance for context-aware responses
  • Async Python provides clean, efficient execution of agent workflows
You can extend this further by adding error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.

How to build RedCircle API MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and RedCircle API MCP?

With a standalone RedCircle API MCP server, the agents and LLMs can only access a fixed set of RedCircle API tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from RedCircle API and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with LangChain?

Yes, you can. LangChain 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 RedCircle API tools.

Can I manage the permissions and scopes for RedCircle API while using Tool Router?

Yes, absolutely. You can configure which RedCircle API 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 RedCircle API data and credentials are handled as safely as possible.

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