How to integrate Quaderno MCP with LangChain

This guide walks you through connecting Quaderno to LangChain using the Composio tool router. By the end, you'll have a working Quaderno agent that can calculate tax rate for a u.s. sale, create an invoice for a new customer, email finalized invoice to a client through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Quaderno account through Composio's Quaderno MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Quaderno

Api Key

Quaderno is a tax compliance platform that automates tax calculations, invoicing, and reporting for businesses globally. It helps you streamline tax processes and stay compliant without manual effort.

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Introduction

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

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

Also integrate Quaderno with

OpenAI Agents SDK Claude Agent SDK Claude Code Claude Cowork Codex OpenClaw Hermes CLI Google ADK Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

Get and set up your OpenAI and Composio API keys
Connect your Quaderno project to Composio
Create a Tool Router MCP session for Quaderno
Initialize an MCP client and retrieve Quaderno tools
Build a LangChain agent that can interact with Quaderno
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 Quaderno MCP server, and what's possible with it?

The Quaderno MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Quaderno account. It provides structured and secure access to your tax automation, invoicing, and compliance workflows, so your agent can calculate taxes, generate invoices, manage contacts and products, and handle essential document delivery on your behalf.

Automated tax rate calculation: Ask your agent to instantly determine the correct tax rate for any address or transaction type before creating invoices or processing sales.
Invoice creation and delivery: Let your agent generate detailed invoices for customers and deliver them directly via email, ensuring seamless billing operations.
Contact and product management: Easily create new customer or vendor contacts, add new products, or permanently delete outdated items from your Quaderno account—all through your agent.
Expense and tax ID cleanup: Direct your agent to remove specific expenses or registered tax IDs when they're no longer needed, keeping your records tidy and up to date.
Credit note and coupon handling: Your agent can deliver finalized credit notes to customers and permanently delete coupons as part of your accounting and revenue operations.

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 step10 STEPS

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

npm install @composio/langchain @langchain/core @langchain/openai @langchain/mcp-adapters 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/core is the core agent framework
dotenv/config 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

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

dotenv.config();

What's happening:

We're importing LangChain's MCP adapter and Composio SDK
The dotenv/config import loads environment variables from your .env file
This setup prepares the foundation for connecting LangChain with Quaderno functionality through MCP

Initialize Composio client

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

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 Quaderno tools
Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

const session = await composio.create(
    userId as string,
    {
        toolkits: ['quaderno']
    }
);

const url = session.mcp.url;

What's happening:

We're creating a Tool Router session that gives your agent access to Quaderno 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 Quaderno tools as needed

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "quaderno-agent": {
        transport: "http",
        url: url,
        headers: {
            "x-api-key": process.env.COMPOSIO_API_KEY
        }
    }
});

const tools = await client.getTools();

const agent = createAgent({ model: "gpt-5", tools });

What's happening:

We're creating a MultiServerMCPClient that connects to our Quaderno MCP server via HTTP
The client is configured with a name and the URL from our Tool Router session
getTools() retrieves all available Quaderno tools that the agent can use
We're creating a LangChain agent using the GPT-5 model

Set up interactive chat interface

let conversationHistory: any[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log("Ask any Quaderno related question or task to the agent.\n");

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

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;
    }

    conversationHistory.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    const response = await agent.invoke({ messages: conversationHistory });
    conversationHistory = response.messages;

    const finalResponse = response.messages[response.messages.length - 1]?.content;
    console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\n👋 Session ended.');
        process.exit(0);
    });

What's happening:

We initialize an empty conversationHistory list to maintain context across interactions
A readline interface is used to continuously accept 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 invoke() method with the full conversation history
Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully

Run the application

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});

What's happening:

We call the main() function to start the application

Complete Code

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

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";  
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

    const session = await composio.create(
        userId as string,
        {
            toolkits: ['quaderno']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "quaderno-agent": {
            transport: "http",
            url: url,
            headers: {
                "x-api-key": process.env.COMPOSIO_API_KEY
            }
        }
    });
    
    const tools = await client.getTools();
  
    const agent = createAgent({ model: "gpt-5", tools });
    
    let conversationHistory: any[] = [];
    
    console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
    console.log("Ask any Quaderno related question or task to the agent.\n");
    
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
        prompt: 'You: '
    });

    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;
        }
        
        conversationHistory.push({ role: "user", content: trimmedInput });
        console.log("\nAgent is thinking...\n");
        
        const response = await agent.invoke({ messages: conversationHistory });
        conversationHistory = response.messages;
        
        const finalResponse = response.messages[response.messages.length - 1]?.content;
        console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\nSession ended.');
        process.exit(0);
    });
}

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});

Conclusion

You've successfully built a LangChain agent that can interact with Quaderno 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.

TOOLS

Supported Tools

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

Add Expense Payment

Adds a payment to an existing expense in Quaderno.

Calculate Tax Rate

Tool to calculate applicable tax rate for given address and transaction type.

Create Contact

Tool to create a new contact (customer or vendor).

Create Coupon

Tool to create a new discount coupon in Quaderno.

Create Estimate

Creates a new estimate/quote in Quaderno for a customer with line items.

Create Evidence

Tool to create a new location evidence for tax compliance.

Create Expense

Tool to create a business expense in Quaderno.

Create Invoice

Creates a new invoice in Quaderno for a customer with line items.

Create Product

Creates a new product that can be used as a line item in invoices, credit notes, and expenses.

Create Receipt

Creates a new receipt in Quaderno documenting payment for goods or services.

Create Recurring

Tool to create a recurring document in Quaderno that automatically generates invoices on a schedule.

Create Report Request

Tool to request a new report generation in Quaderno.

Create Tax ID

Tool to create a tax ID in a specific jurisdiction.

Create Transaction

Tool to create a sale or refund transaction in Quaderno.

Create Webhook

Tool to create a new webhook in Quaderno to receive event notifications.

Delete Contact

Tool to permanently delete a contact by ID.

Delete Coupon

Tool to permanently delete a coupon.

Delete Estimate

Permanently deletes an estimate from Quaderno by its ID.

Delete Expense

Permanently deletes an expense from Quaderno by its ID.

Delete Product

Tool to permanently delete a product by ID.

Delete Recurring

Tool to permanently delete a recurring by ID.

Delete Tax ID

Permanently deletes a registered tax ID from your Quaderno account.

Delete Webhook

Tool to permanently delete a webhook by ID.

Deliver Credit Note

Sends a credit note to the customer via email.

Deliver Estimate

Delivers an estimate to the customer via email.

Deliver Invoice

Delivers an invoice to the customer via email.

Deliver Receipt

Sends a receipt to the customer via email.

Get Authorization

Tool to retrieve account credentials and verify API access.

Get Estimate

Tool to retrieve the details of an existing estimate by ID.

List Contacts

Tool to list contacts, paginated and filterable by name, email, or tax ID.

List Coupons

Tool to list all coupons.

List Credits

Tool to list all credit notes from Quaderno.

List Estimates

Tool to list all estimates in the account, paginated and sorted by creation date (newest first).

List Evidence

Tool to list all evidence objects.

List Expenses

List all expenses from Quaderno with pagination support.

List Invoices

Tool to list all invoices from Quaderno with filtering support.

List Tax Jurisdictions

Tool to list all tax jurisdictions.

List Products

List all products (goods and services) from your Quaderno account.

List Receipts

Tool to list all receipts from Quaderno with optional filtering by search query, date range, payment state, processor ID, or customer ID.

List Recurrings

List all recurring documents (invoices, expenses, or estimates) from your Quaderno account.

List Registered Tax IDs

Tool to list all registered tax IDs.

List Reporting Requests

Retrieves all reporting requests for the account with their current status and download URLs.

List Sessions

List Quaderno Checkout sessions with optional filtering and pagination.

List Tax Codes

Tool to list all supported tax codes.

List Webhooks

Tool to list all webhooks.

Mark Invoice Uncollectible

Tool to mark an invoice as uncollectible (bad debt).

Ping API Service

Tool to check if the Quaderno API service is up and verify credentials.

Record Invoice Payment

Tool to record a payment on an existing invoice.

Remove Invoice Payment

Tool to remove a payment from an invoice.

Retrieve Contact

Tool to retrieve details of an existing contact by ID.

Retrieve Contact by Processor ID

Tool to retrieve a contact by external payment processor customer ID and gateway name.

Retrieve Coupon

Retrieve detailed information about a specific coupon by its ID.

Retrieve Credit Note

Tool to retrieve details of an existing credit note by ID.

Retrieve Evidence

Retrieves a specific evidence object by its ID.

Retrieve Expense

Tool to retrieve details of an existing expense by ID.

Retrieve Invoice

Tool to retrieve details of an existing invoice by ID.

Retrieve Tax Jurisdiction

Tool to retrieve a tax jurisdiction by ID.

Retrieve Product

Tool to retrieve details of an existing product by ID.

Retrieve Receipt

Tool to retrieve details of an existing receipt by ID.

Retrieve Recurring

Tool to retrieve details of an existing recurring document by ID.

Retrieve Reporting Request

Tool to retrieve the status and download URL of a specific report request by ID.

Retrieve Tax Code

Tool to retrieve a specific tax code by ID.

Retrieve Tax ID

Tool to retrieve details of a specific tax ID by its ID.

Update Contact

Tool to update an existing contact in Quaderno.

Update Coupon

Tool to update an existing coupon.

Update Credit Note

Tool to update a credit note.

Update Estimate

Updates an existing estimate in Quaderno by modifying allowed fields.

Update Evidence

Tool to update an evidence object.

Update Expense

Updates an existing expense in Quaderno by modifying allowed fields.

Update Invoice

Updates an existing invoice in Quaderno by modifying allowed fields.

Update product

Tool to update a product; unspecified fields remain unchanged.

Update Recurring

Tool to update a recurring document in Quaderno.

Update Tax ID

Tool to update an existing tax ID in Quaderno.

Update Webhook

Tool to update an existing webhook configuration.

Validate Tax ID

Tool to validate a tax ID.

Void Credit Note

Tool to void a credit note.

FRAMEWORKS

How to build Quaderno MCP Agent with another framework

OpenAI Agents SDK

Use Quaderno MCP with OpenAI Agents SDK

Claude Agent SDK

Use Quaderno MCP with Claude Agent SDK

Claude Code

Use Quaderno MCP with Claude Code

Claude Cowork

Use Quaderno MCP with Claude Cowork

Codex

Use Quaderno MCP with Codex

OpenClaw

Use Quaderno MCP with OpenClaw

Hermes

Use Quaderno MCP with Hermes

CLI

Use Quaderno MCP with CLI

Google ADK

Use Quaderno MCP with Google ADK

Vercel AI SDK

Use Quaderno MCP with Vercel AI SDK

Mastra AI

Use Quaderno MCP with Mastra AI

LlamaIndex

Use Quaderno MCP with LlamaIndex

CrewAI

Use Quaderno MCP with CrewAI

MORE TOOLKITS

Explore Other Toolkits

Toolkit marketplace

Stripe

Api KeyOauth2

Stripe is a global online payments platform offering APIs for managing payments, customers, and subscriptions. Trusted by businesses for secure, efficient, and scalable payment processing worldwide.

Alpha vantage

Api Key

Alpha Vantage is a financial data platform offering real-time and historical stock market APIs. Get instant, reliable access to equities, forex, and technical analysis data for smarter trading decisions.

Altoviz

Api Key

Altoviz is a cloud-based billing and invoicing platform for businesses. It streamlines online payments, expense tracking, and customizable invoice management.

Benzinga

Api Key

Benzinga provides real-time financial news and data APIs for market coverage. It helps you track breaking news and actionable market insights instantly.

FAQ

Frequently asked questions

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

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 Quaderno tools.

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

Start with Quaderno.It takes 30 seconds.

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

Start building

Customer stories

Teams ship real agents on Composio

GET STARTED FOR FREE BOOK A DEMO

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 Quaderno MCP with LangChain

Connect Quaderno without auth hassles

Introduction

Also integrate Quaderno with

TL;DR

What is LangChain?

What is the Quaderno 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 OpenAI and Composio

Install dependencies

Set up environment variables

Import dependencies

Initialize Composio client

Create a Tool Router session

Configure the agent with the MCP URL

Set up interactive chat interface

Run the application

Complete Code

Conclusion

Supported Tools

How to build Quaderno MCP Agent with another framework

OpenAI Agents SDK

Claude Agent SDK

Claude Code

Claude Cowork

Codex

OpenClaw

Hermes

CLI

Google ADK

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

Explore Other Toolkits

Stripe

Alpha vantage

Altoviz

Benzinga

Frequently asked questions

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

Can I use Tool Router MCP with LangChain?+

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

How safe is my data with Composio Tool Router?+

Start with Quaderno.It takes 30 seconds.

Teams ship real agents on Composio