How to integrate Erpnext MCP with LangChain

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Introduction

This guide walks you through connecting Erpnext to LangChain using the Composio tool router. By the end, you'll have a working Erpnext agent that can list overdue tasks for all projects, create a new customer record, get all open purchase orders through natural language commands.

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

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

Supported Tools & Triggers

Tools
Add CommentTool to add a comment to a document in ERPNext/Frappe.
Add TagTool to add a tag to a document in ERPNext.
Apply WorkflowTool to apply a workflow action to a document in ERPNext/Frappe.
Cancel DocumentCancel a submitted document in ERPNext/Frappe to change its status from Submitted to Cancelled.
Create DocumentTool to create a new document of a specific DocType in ERPNext.
Create TimesheetTool to create a new Timesheet record in ERPNext.
Create WebhookTool to create a new webhook configuration in ERPNext.
Delete DocumentTool to delete a document using the Frappe client API.
Delete DocumentTool to delete a specific document by DocType and name.
Download file from ERPNextTool to download a file from ERPNext by its URL.
Download PDF DocumentTool to download a document as PDF from ERPNext with optional print format.
Get All LanguagesTool to get a list of all available languages in the ERPNext/Frappe system.
Get All RolesTool to get a list of all roles available in the ERPNext system.
Get DocumentTool to get a single document by DocType and name or filters from Frappe/ERPNext.
Get Document CountTool to get the count of documents matching specified filters in ERPNext/Frappe.
Get DocType MetadataTool to retrieve complete DocType metadata/schema including field definitions, field types, permissions, and configurations.
Get DocumentTool to retrieve a specific document by its DocType and name (ID).
Get Document with MetadataTool to retrieve a document with full metadata including attachments, comments, activity logs, and related information.
Get Exchange RateTool to get the currency exchange rate between two currencies in ERPNext.
Get Fiscal YearTool to get fiscal year information for a given date in ERPNext.
Get Framework VersionTool to get the Frappe framework version and all installed app versions.
Get Item DetailsTool to get detailed item information including pricing, taxes, and stock details from ERPNext.
Get List of DocumentsTool to retrieve a list of documents from ERPNext/Frappe with filtering, field selection, and pagination.
Get Logged UserTool to get the email/ID of the currently authenticated user.
Get Party DetailsTool to get comprehensive customer or supplier details including addresses, contacts, and default financial settings.
Get Payment EntryTool to get payment entry details for an invoice or order from ERPNext.
Get Stock BalanceTool to retrieve the current stock balance for a specific item in a warehouse.
Get TimezonesTool to get a list of all available timezones in the ERPNext system.
Get User RolesTool to get roles assigned to a user.
Get Field ValueTool to get specific field value(s) from a document in ERPNext.
Get Workflow TransitionsTool to get available workflow transitions for a document.
Insert DocumentTool to insert a new document in ERPNext/Frappe using the client API.
Insert Multiple DocumentsTool to insert multiple documents at once into ERPNext/Frappe.
List DocTypesTool to get a list of all DocTypes available in the ERPNext system.
List ERPNext DocumentsTool to list documents of a specific DocType from ERPNext.
List EmployeesTool to retrieve a list of Employee records from ERPNext.
List ProjectsTool to retrieve a list of Project records from ERPNext.
List TimesheetsTool to get a list of Timesheet records from ERPNext.
List WebhooksTool to list webhook configurations in ERPNext.
Make Delivery NoteCreate a draft Delivery Note from an existing Sales Order in ERPNext.
Make Purchase OrderCreate a draft Purchase Order from an existing Material Request in ERPNext.
Make Sales InvoiceTool to create a Sales Invoice from an existing Sales Order in ERPNext.
Make Stock EntryTool to create a Stock Entry for material transfer, receipt, or issue in ERPNext.
Ping APITool to check if the ERPNext/Frappe API is reachable.
Rename DocumentTool to rename an ERPNext document by changing its unique ID/name.
Save Document with ActionTool to save, submit, cancel, or update a document in ERPNext.
Save DocumentTool to save an existing ERPNext/Frappe document with changes.
Global SearchTool to perform global text search across ERPNext documents.
Search Link Field DocumentsTool to search for documents to link in ERPNext/Frappe Link fields.
Set ValueTool to set a specific field value on a document in ERPNext.
Submit DocumentSubmit a draft document in ERPNext/Frappe to change its status from Draft to Submitted.
Update ERPNext documentTool to update a specific ERPNext document.

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

Create a Tool Router session

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

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

Configure the agent with the MCP URL

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

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

FAQ

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

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

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

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

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