How to integrate Quaderno MCP with Google ADK

This guide walks you through connecting Quaderno to Google ADK 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 Google ADK 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 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.

76 Tools

Introduction

This guide walks you through connecting Quaderno to Google ADK 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 Google ADK 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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TL;DR

Here's what you'll learn:
  • Get a Quaderno account set up and connected to Composio
  • Install the Google ADK and Composio packages
  • Create a Composio Tool Router session for Quaderno
  • Build an agent that connects to Quaderno through MCP
  • Interact with Quaderno using natural language

What is Google ADK?

Google ADK (Agents Development Kit) is Google's framework for building AI agents powered by Gemini models. It provides tools for creating agents that can use external services through the Model Context Protocol.

Key features include:

  • Gemini Integration: Native support for Google's Gemini models
  • MCP Toolset: Built-in support for Model Context Protocol tools
  • Streamable HTTP: Connect to external services through streamable HTTP
  • CLI and Web UI: Run agents via command line or web interface

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:

  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

Step by step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • A Google API key for Gemini models
  • A Composio account and API key
  • Python 3.9 or later installed
  • Basic familiarity with Python
2

Getting API Keys for Google and Composio

Google API Key
  • Go to Google AI Studio and create an API key.
  • Copy the key and keep it safe. You will put this in GOOGLE_API_KEY.
Composio API Key and User ID
  • Log in to the Composio dashboard.
  • Go to Settings → API Keys and copy your Composio API key. Use this for COMPOSIO_API_KEY.
  • Decide on a stable user identifier to scope sessions, often your email or a user ID. Use this for COMPOSIO_USER_ID.
3

Install dependencies

bash
pip install google-adk composio python-dotenv

Inside your virtual environment, install the required packages.

What's happening:

  • google-adk is Google's Agents Development Kit
  • composio connects your agent to Quaderno via MCP
  • python-dotenv loads environment variables
4

Set up ADK project

bash
adk create my_agent

Set up a new Google ADK project.

What's happening:

  • This creates an agent folder with a root agent file and .env file
5

Set environment variables

bash
GOOGLE_API_KEY=your-google-api-key
COMPOSIO_API_KEY=your-composio-api-key
COMPOSIO_USER_ID=your-user-id-or-email

Save all your credentials in the .env file.

What's happening:

  • GOOGLE_API_KEY authenticates with Google's Gemini models
  • COMPOSIO_API_KEY authenticates with Composio
  • COMPOSIO_USER_ID identifies the user for session management
6

Import modules and validate environment

python
import os
import warnings

from composio import Composio
from dotenv import load_dotenv
from google.adk.agents.llm_agent import Agent
from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnectionParams
from google.adk.tools.mcp_tool.mcp_toolset import McpToolset

load_dotenv()

warnings.filterwarnings("ignore", message=".*BaseAuthenticatedTool.*")

GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
COMPOSIO_API_KEY = os.getenv("COMPOSIO_API_KEY")
COMPOSIO_USER_ID = os.getenv("COMPOSIO_USER_ID")

if not GOOGLE_API_KEY:
    raise ValueError("GOOGLE_API_KEY is not set in the environment.")
if not COMPOSIO_API_KEY:
    raise ValueError("COMPOSIO_API_KEY is not set in the environment.")
if not COMPOSIO_USER_ID:
    raise ValueError("COMPOSIO_USER_ID is not set in the environment.")
What's happening:
  • os reads environment variables
  • Composio is the main Composio SDK client
  • GoogleProvider declares that you are using Google ADK as the agent runtime
  • Agent is the Google ADK LLM agent class
  • McpToolset lets the ADK agent call MCP tools over HTTP
7

Create Composio client and Tool Router session

python
composio_client = Composio(api_key=COMPOSIO_API_KEY)

composio_session = composio_client.create(
    user_id=COMPOSIO_USER_ID,
    toolkits=["quaderno"],
)

COMPOSIO_MCP_URL = composio_session.mcp.url,
print(f"Composio MCP URL: {COMPOSIO_MCP_URL}")
What's happening:
  • Authenticates to Composio with your API key
  • Declares Google ADK as the provider
  • Spins up a short-lived MCP endpoint for your user and selected toolkit
  • Stores the MCP HTTP URL for the ADK MCP integration
8

Set up the McpToolset and create the Agent

python
composio_toolset = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url=COMPOSIO_MCP_URL,
        headers={"x-api-key": COMPOSIO_API_KEY}
    )
)

root_agent = Agent(
    model="gemini-2.5-flash",
    name="composio_agent",
    description="An agent that uses Composio tools to perform actions.",
    instruction=(
        "You are a helpful assistant connected to Composio. "
        "You have the following tools available: "
        "COMPOSIO_SEARCH_TOOLS, COMPOSIO_MULTI_EXECUTE_TOOL, "
        "COMPOSIO_MANAGE_CONNECTIONS, COMPOSIO_REMOTE_BASH_TOOL, COMPOSIO_REMOTE_WORKBENCH. "
        "Use these tools to help users with Quaderno operations."
    ),
    tools=[composio_toolset],
)

print("\nAgent setup complete. You can now run this agent directly ;)")
What's happening:
  • Connects the ADK agent to the Composio MCP endpoint through McpToolset
  • Uses Gemini as the model powering the agent
  • Lists exact tool names in instruction to reduce misnamed tool calls
9

Run the agent

bash
# Run in CLI mode
adk run my_agent

# Or run in web UI mode
adk web

Execute the agent from the project root. The web command opens a web portal where you can chat with the agent.

What's happening:

  • adk run runs the agent in CLI mode
  • adk web . opens a web UI for interactive testing

Complete Code

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

python
import os
import warnings

from composio import Composio
from composio_google import GoogleProvider
from dotenv import load_dotenv
from google.adk.agents.llm_agent import Agent
from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnectionParams
from google.adk.tools.mcp_tool.mcp_toolset import McpToolset

load_dotenv()
warnings.filterwarnings("ignore", message=".*BaseAuthenticatedTool.*")

GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
COMPOSIO_API_KEY = os.getenv("COMPOSIO_API_KEY")
COMPOSIO_USER_ID = os.getenv("COMPOSIO_USER_ID")

if not GOOGLE_API_KEY:
    raise ValueError("GOOGLE_API_KEY is not set in the environment.")
if not COMPOSIO_API_KEY:
    raise ValueError("COMPOSIO_API_KEY is not set in the environment.")
if not COMPOSIO_USER_ID:
    raise ValueError("COMPOSIO_USER_ID is not set in the environment.")

composio_client = Composio(api_key=COMPOSIO_API_KEY, provider=GoogleProvider())

composio_session = composio_client.create(
    user_id=COMPOSIO_USER_ID,
    toolkits=["quaderno"],
)

COMPOSIO_MCP_URL = composio_session.mcp.url


composio_toolset = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url=COMPOSIO_MCP_URL,
        headers={"x-api-key": COMPOSIO_API_KEY}
    )
)

root_agent = Agent(
    model="gemini-2.5-flash",
    name="composio_agent",
    description="An agent that uses Composio tools to perform actions.",
    instruction=(
        "You are a helpful assistant connected to Composio. "
        "You have the following tools available: "
        "COMPOSIO_SEARCH_TOOLS, COMPOSIO_MULTI_EXECUTE_TOOL, "
        "COMPOSIO_MANAGE_CONNECTIONS, COMPOSIO_REMOTE_BASH_TOOL, COMPOSIO_REMOTE_WORKBENCH. "
        "Use these tools to help users with Quaderno operations."
    ),  
    tools=[composio_toolset],
)

print("\nAgent setup complete. You can now run this agent directly ;)")

Conclusion

You've successfully integrated Quaderno with the Google ADK through Composio's MCP Tool Router. Your agent can now interact with Quaderno using natural language commands.

Key takeaways:

  • The Tool Router approach dynamically routes requests to the appropriate Quaderno tools
  • Environment variables keep your credentials secure and separate from code
  • Clear agent instructions reduce tool calling errors
  • The ADK web UI provides an interactive interface for testing and development

You can extend this setup by adding more toolkits to the toolkits array in your session configuration.

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.

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. Google ADK 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.

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