How to integrate Rentman MCP with LangChain

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Introduction

This guide walks you through connecting Rentman to LangChain using the Composio tool router. By the end, you'll have a working Rentman agent that can list all crew assignments for this week, show available equipment for project 1234, create new project booking for next month through natural language commands.

This guide will help you understand how to give your LangChain agent real control over a Rentman account through Composio's Rentman 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 Rentman project to Composio
  • Create a Tool Router MCP session for Rentman
  • Initialize an MCP client and retrieve Rentman tools
  • Build a LangChain agent that can interact with Rentman
  • 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 Rentman MCP server, and what's possible with it?

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

Supported Tools & Triggers

Tools
Delete AppointmentTool to delete an appointment by its unique ID.
Delete Appointmentcrew ItemTool to delete an appointmentcrew item by its numeric ID.
Delete ContactTool to delete a contact by its ID.
Delete contact personTool to delete a contact person from Rentman by their numeric ID.
Delete Cost ItemTool to delete a cost item in Rentman by its numeric ID.
Delete Crew AvailabilityTool to delete a crew availability item by its ID.
Delete Project RequestTool to delete a project request by its ID.
Delete Project Request Equipment ItemTool to delete a project request equipment item by its ID.
Delete Time RegistrationTool to delete a time registration item in Rentman by its numeric ID.
Get Accessories CollectionTool to retrieve a collection of accessories from Rentman.
Get Appointment CrewTool to retrieve the linked crew members for a specific appointment.
Get Appointmentcrew CollectionTool to retrieve appointmentcrew collection from Rentman.
Get Appointments CollectionTool to retrieve a collection of appointments from Rentman.
Get Contact ContactpersonsTool to retrieve all contactpersons linked to a specific contact in Rentman.
Get Contact File FoldersTool to get file folders linked to a contact.
Get Contact FilesTool to get files linked to a contact.
Get Contact Person File FoldersTool to retrieve file folders linked to a contact person in Rentman.
Get Contact Person FilesTool to retrieve files linked to a contact person in Rentman.
Get Contact PersonsTool to retrieve the collection of contact persons from Rentman.
Get Contacts CollectionTool to retrieve a collection of contacts from Rentman.
Get contract invoicelinesRetrieves invoicelines linked to a specific contract.
Get Contract FilesTool to retrieve files linked to a specific contract.
Get Contracts CollectionTool to retrieve a collection of contracts from Rentman.
Get Costs CollectionTool to retrieve costs collection from Rentman.
Get Crew Member AppointmentsTool to retrieve appointments for a specific crew member.
Get Crew AvailabilityTool to retrieve crew availability records for a specific crew member in Rentman.
Get Crew Availability CollectionTool to retrieve crew availability collection from Rentman.
Get Crew CollectionTool to retrieve crew collection from Rentman.
Get Crew File FoldersTool to retrieve file folders linked to a crew member.
Get Crew FilesTool to retrieve files linked to a crew member.
Get Crew MemberTool to retrieve a crew member item by ID from Rentman.
Get Crewrates CollectionTool to retrieve crewrates collection from Rentman.
Get Crew RatesTool to get crew rates linked collection for a specific crew member.
Get Equipment AccessoriesTool to get accessories linked to a specific equipment item.
Get equipment collectionTool to get the equipment collection from Rentman.
Get Equipment File FoldersTool to get file folders linked to equipment.
Get Equipment FilesTool to get files linked to equipment.
Get Equipment RepairsTool to retrieve repairs linked to a specific equipment item.
Get Equipment Serial NumbersTool to retrieve serial numbers linked to a specific equipment item.
Get Equipment Sets Content CollectionTool to retrieve the equipment sets content collection from Rentman.
Get Equipment Sets ContentTool to get equipment sets content linked collection for a specific equipment item.
Get Equipment StockmovementsTool to get stockmovements linked collection for a specific equipment item.
Get Files CollectionTool to retrieve files collection from Rentman.
Get Folder ItemTool to retrieve a folder item by ID from Rentman.
Get Folders CollectionTool to retrieve folders collection from Rentman.
Get Invoice FilesTool to retrieve files linked to an invoice in Rentman.
Get Invoice InvoicelinesTool to retrieve invoicelines linked to a specific invoice.
Get Invoice LinesTool to retrieve invoicelines collection from Rentman.
Get Invoice PaymentsTool to retrieve payments linked to a specific invoice.
Get Invoices CollectionTool to retrieve a collection of invoices from Rentman.
Get Ledgercodes CollectionTool to retrieve ledger codes collection from Rentman.
Get Payments CollectionTool to retrieve a collection of payments from Rentman.
Get Project ContractsTool to retrieve contracts linked to a specific project from Rentman.
Get Project CostsTool to retrieve costs linked to a specific project from Rentman.
Get Projectcrew CollectionTool to retrieve projectcrew collection from Rentman.
Get Project Equipment CollectionTool to retrieve a collection of project equipment from Rentman.
Get Projectequipmentgroup CollectionTool to retrieve projectequipmentgroup collection from Rentman.
Get project equipment group project equipmentTool to get projectequipment linked collection for a specific projectequipmentgroup.
Get Project File FoldersTool to retrieve file folders linked to a specific project.
Get Project FilesTool to retrieve files linked to a project.
Get Project Function Group Project FunctionsTool to get project functions linked to a specific project function group in Rentman.
Get Project Function Groups CollectionTool to retrieve a collection of project function groups from Rentman.
Get Project Function CrewTool to get project crew linked to a specific project function.
Get Projectfunction ProjectvehiclesTool to retrieve project vehicles linked to a project function.
Get Projectfunctions CollectionTool to retrieve a collection of projectfunctions from Rentman.
Get Project CrewTool to get project crew custom linked collection for a specific project.
Get Project EquipmentTool to retrieve all equipment items linked to a specific project in Rentman.
Get project projectequipmentgroupTool to get projectequipmentgroup linked collection for a specific project.
Get Project Function Groups For ProjectTool to retrieve project function groups linked to a specific project in Rentman.
Get Project ProjectfunctionsTool to retrieve projectfunctions linked to a specific project.
Get Project ProjectvehiclesTool to retrieve project vehicles linked to a project.
Get Project QuotesTool to retrieve quotes linked to a project.
Get Project Request EquipmentTool to retrieve projectrequestequipment linked to a specific project request in Rentman.
Get Project Request Equipment CollectionTool to retrieve project request equipment collection from Rentman.
Get Project Requests CollectionTool to retrieve a collection of project requests from Rentman.
Get Projects CollectionTool to retrieve a collection of projects from Rentman.
Get Project SubprojectsTool to retrieve subprojects linked to a specific project from Rentman.
Get Projecttypes CollectionTool to retrieve a collection of project types from Rentman.
Get Projectvehicles CollectionTool to retrieve projectvehicles collection from Rentman.
Get Quote FilesTool to get files linked to a quote.
Get quote invoicelinesRetrieves invoicelines linked to a specific quote.
Get Quotes CollectionTool to retrieve a collection of quotes from Rentman.
Get Ratefactors CollectionTool to retrieve a collection of ratefactors from Rentman.
Get Rate RatefactorsTool to retrieve the ratefactors custom linked collection for a specific rate.
Get Rates CollectionTool to retrieve rates collection from Rentman.
Get Repair File FoldersTool to get file folders linked to a repair.
Get Repair FilesTool to get files linked to a repair.
Get Repairs CollectionTool to retrieve a collection of repairs from Rentman.
Get Serial Number File FoldersTool to get file folders linked to a serial number.
Get Serial Number FilesTool to get files linked to a serial number.
Get Serialnumbers CollectionTool to retrieve a collection of serialnumbers from Rentman.
Get Statuses CollectionTool to retrieve a collection of statuses from Rentman.
Get Stocklocations CollectionTool to retrieve stock locations collection from Rentman.
Get Stockmovements CollectionTool to retrieve the stock movements collection from Rentman.
Get Subproject File FoldersTool to get file folders linked to a subproject.
Get Subproject Project CrewTool to get project crew custom linked collection for a specific subproject.
Get Subproject Project EquipmentTool to retrieve project equipment collection from a specific subproject in Rentman.
Get subproject projectequipmentgroupTool to get projectequipmentgroup linked collection for a specific subproject.
Get Project Function Groups For SubprojectTool to retrieve project function groups linked to a specific subproject in Rentman.
Get Subproject ProjectvehiclesTool to retrieve project vehicles linked to a subproject.
Get Subprojects CollectionTool to retrieve subprojects collection from Rentman.
Get Subrental Equipment CollectionTool to retrieve a collection of subrental equipment items from Rentman.
Get Subrental Equipment GroupTool to get subrental equipment group custom linked collection from Rentman.
Get Subrental Equipment Group CollectionTool to retrieve the complete collection of subrental equipment groups from Rentman.
Get subrental equipment group subrental equipmentTool to get subrentalequipment custom linked collection for a specific subrentalequipmentgroup.
Get Subrental File FoldersTool to get file folders linked to a subrental.
Get Subrental FilesTool to get files linked to a subrental.
Get Subrentals CollectionTool to get subrentals collection from Rentman.
Get Subrental SubrentalequipmentTool to retrieve subrentalequipment linked to a specific subrental in Rentman.
Get Tax Classes CollectionTool to retrieve a collection of tax classes from Rentman.
Get Timeregistration ActivitiesTool to retrieve all timeregistrationactivities linked to a specific timeregistration in Rentman.
Get Timeregistration Activities CollectionTool to retrieve a collection of timeregistration activities from Rentman.
Get Timeregistration CollectionTool to retrieve a collection of timeregistrations from Rentman.
Get Time Registration FilesTool to get files linked to a time registration.
Get Vehicle File FoldersTool to get file folders linked to a vehicle.
Get Vehicle FilesTool to get files linked to a vehicle.
Get Vehicles CollectionTool to retrieve a collection of vehicles from Rentman.
List ActualcontentTool to get actualcontent collection from Rentman.
List Equipmentassignedserials CollectionTool to retrieve serial numbers assigned to serialized physical combinations from Rentman.
List FactorgroupsTool to retrieve factorgroups collection from Rentman.
List Factorgroups FactorsTool to retrieve the factors collection for a specific factorgroup.
List FactorsTool to retrieve a collection of factors from Rentman.
List File FoldersTool to retrieve file folders collection from Rentman.
List Leave MutationsTool to retrieve leave mutations collection from Rentman.
List Leave RequestsTool to retrieve leave requests collection from Rentman.
List Leave Request TimeregistrationTool to get timeregistration collection for a specific leave request.
List Leave TypesTool to retrieve leave types collection from Rentman.
List Serialnumber ActualcontentTool to retrieve the actualcontent collection for a specific serialnumber item.
List Serialnumber Equipment Assigned SerialsTool to retrieve equipmentassignedserials collection for a specific serialnumber item.
List Stocklocations VehiclesTool to retrieve vehicles collection for a stocklocation.

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 Rentman 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 Rentman tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

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

url = session.mcp.url
What's happening:
  • We're creating a Tool Router session that gives your agent access to Rentman 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 Rentman tools as needed

Configure the agent with the MCP URL

client = MultiServerMCPClient({
    "rentman-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 Rentman MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • get_tools() retrieves all available Rentman 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 Rentman 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 Rentman 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=['rentman']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "rentman-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 Rentman 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 Rentman 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 Rentman MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Rentman MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Rentman MCP with Claude Agent SDK

Google ADK

Google ADK

Use Rentman MCP with Google ADK

Vercel AI SDK

Vercel AI SDK

Use Rentman MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Rentman MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Rentman MCP with LlamaIndex

CrewAI

CrewAI

Use Rentman MCP with CrewAI

Claude Code

Claude Code

Use Rentman MCP with Claude Code

Codex

Codex

Use Rentman MCP with Codex

FAQ

What are the differences in Tool Router MCP and Rentman MCP?

With a standalone Rentman MCP server, the agents and LLMs can only access a fixed set of Rentman tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Rentman 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 Rentman tools.

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

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

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