How to integrate Dropbox sign MCP with Pydantic AI

This guide walks you through connecting Dropbox sign to Pydantic AI using the Composio tool router. By the end, you'll have a working Dropbox sign agent that can send nda for signature to new hire, get status of recent signature requests, download signed contract from last week through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Dropbox sign account through Composio's Dropbox sign MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

Dropbox sign logoDropbox sign
Api KeyOauth2

Dropbox Sign is an electronic signature platform for sending, signing, and managing legally binding documents online. It streamlines business workflows by making signature collection fast, secure, and effortless.

56 Tools

Introduction

This guide walks you through connecting Dropbox sign to Pydantic AI using the Composio tool router. By the end, you'll have a working Dropbox sign agent that can send nda for signature to new hire, get status of recent signature requests, download signed contract from last week through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Dropbox sign account through Composio's Dropbox sign 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:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Dropbox sign
  • How to attach an MCP Server to a Pydantic AI agent
  • How to stream responses and maintain chat history
  • How to build a simple REPL-style chat interface to test your Dropbox sign workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

  • Type Safety: Built on Pydantic for automatic data validation
  • MCP Support: Native support for Model Context Protocol servers
  • Streaming: Built-in support for streaming responses
  • Async First: Designed for async/await patterns

What is the Dropbox sign MCP server, and what's possible with it?

The Dropbox sign MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Dropbox Sign account. It provides structured and secure access to your e-signature workflows, so your agent can prepare signature requests, manage documents, track signing progress, and automate agreement workflows on your behalf.

  • Automated signature requests: Have your agent create, send, and manage legally binding signature requests to one or multiple recipients, streamlining document approval processes.
  • Template-based document preparation: Let your agent generate documents from templates, pre-fill fields, and quickly send out repeat agreements without manual editing.
  • Status tracking and reminders: Ask your agent to monitor the progress of signature requests, check who has signed, and send automated reminders to outstanding signers as needed.
  • Secure document storage and retrieval: Effortlessly fetch completed, pending, or archived documents, download signed agreements, and keep your workflow organized and compliant.
  • Audit trails and activity logs: Access detailed audit trails and event histories for every document, so you can maintain compliance and always know who did what, and when.

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:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming
2

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.
3

Install dependencies

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

  • composio connects your agent to external SaaS tools like Dropbox sign
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your agent to Composio's API
  • USER_ID associates your session with your account for secure tool access
  • OPENAI_API_KEY to access OpenAI LLMs
5

Import dependencies

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()
What's happening:
  • We load environment variables and import required modules
  • Composio manages connections to Dropbox sign
  • MCPServerStreamableHTTP connects to the Dropbox sign MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant
6

Create a Tool Router Session

python
async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Dropbox sign
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["dropbox_sign"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")
What's happening:
  • We're creating a Tool Router session that gives your agent access to Dropbox sign 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
7

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
dropbox_sign_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[dropbox_sign_mcp],
    instructions=(
        "You are a Dropbox sign assistant. Use Dropbox sign tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Dropbox sign endpoint
  • The agent uses GPT-5 to interpret user commands and perform Dropbox sign operations
  • The instructions field defines the agent's role and behavior
8

Build the chat interface

python
# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Dropbox sign.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()
What's happening:
  • The agent reads input from the terminal and streams its response
  • Dropbox sign API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns
9

Run the application

python
if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Dropbox sign and Pydantic AI:

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Dropbox sign
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["dropbox_sign"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    dropbox_sign_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[dropbox_sign_mcp],
        instructions=(
            "You are a Dropbox sign assistant. Use Dropbox sign tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Dropbox sign.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

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

Conclusion

You've built a Pydantic AI agent that can interact with Dropbox sign through Composio's Tool Router. With this setup, your agent can perform real Dropbox sign actions through natural language. You can extend this further by:
  • Adding other toolkits like Gmail, HubSpot, or Salesforce
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Dropbox sign for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.
TOOLS

Supported Tools

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

Invite User to Team

Tool to invite a user to your Team.

Add User to Template

Tool to grant a specified account access to a template.

Bulk create embedded signature request with template

Tool to create a BulkSendJob for embedded templated signature requests.

Bulk send with template

Tool to create a BulkSendJob for templated signature requests.

Cancel Signature Request

Cancels an incomplete signature request.

Create Dropbox Sign Account

Tool to create a new Dropbox Sign account associated with a specified email address.

Create API App

Tool to create a new Dropbox Sign API App.

Create Embedded Signature Request

Tool to create an embedded signature request for signing in an iFrame.

Create Embedded Signature Request With Template

Tool to create an embedded signature request based on a template.

Create Embedded Template Draft

Tool to create an embedded template draft.

Create Embedded Unclaimed Draft with Template

Tool to create an embedded unclaimed draft using saved templates.

Create Report

Request creation of CSV report(s) for a specified date range.

Create Template

Tool to create a reusable template for document signing workflows.

Create Unclaimed Draft

Tool to create an unclaimed draft that can be claimed via a unique URL.

Delete API App

Tool to delete an API App from your Dropbox Sign account by its client_id.

Delete Fax

Tool to delete a fax from the system by its fax_id.

Delete Template

Permanently deletes a template from your Dropbox Sign account by its template_id.

Download Signature Request Files

Download files for a signature request as PDF (merged) or ZIP (individual documents).

Edit and Resend Embedded Signature Request

Tool to edit and resend an embedded signature request.

Edit and Resend Signature Request

Edits and resends an existing non-templated signature request with updated documents, signers, or settings.

Edit and Resend Unclaimed Draft

Tool to edit and resend a previously created unclaimed draft.

Edit and Resend Embedded Signature Request With Template

Tool to edit and resend an embedded signature request using templates.

Get Dropbox Sign Account

Retrieves detailed information about a Dropbox Sign account including quotas, payment status, and settings.

Get API App

Tool to retrieve information about an API App by its client ID.

Get Bulk Send Job

Tool to retrieve the status of a bulk send job.

Get Current Team Membership

Tool to get the current team membership status and details.

Get Embedded Sign URL

Retrieves an embedded signing URL for a specific signer's signature.

Get Embedded Template Edit URL

Tool to generate an edit URL for embedded template editing.

Get Available Fax Line Area Codes

Tool to retrieve available fax line area codes for a given country, state/province, and city.

Get Signature Request

Retrieves the current status and complete details of a signature request by ID.

Get Signature Request Files as Data URI

Tool to download signature request files as a base64-encoded data URI.

Get Signature Request Files as File URL

Retrieves a copy of the current documents and returns a JSON object with a URL to the file (PDFs only).

Get Team Info

Retrieves information about a Dropbox Sign team, including team name, member count, and sub-team count.

Get Template

Tool to return the specified template.

Download Template Files

Tool to download documents associated with a template.

Get Template Files as Data URI

Tool to retrieve template documents as base64-encoded data URI.

Get Template Files as File URL

Tool to retrieve a copy of template documents and return a JSON object with a URL to the file (PDFs only).

List API Apps

Tool to list API Apps.

List Bulk Send Jobs

Tool to list bulk send jobs.

List Faxes

Tool to list faxes and their properties.

List Fax Lines

Tool to list fax lines and their properties.

List Signature Requests

Tool to list signature requests.

List Sub-Teams

Lists all sub-teams belonging to a parent team with pagination support.

List Team Members

Lists all members and their roles for a specific team.

List All Teams

Lists all Dropbox Sign teams accessible to the authenticated user, including the current team and its sub-teams.

List Templates

Tool to list templates.

Generate OAuth Authorization URL

Tool to generate an OAuth authorization URL.

Release Signature Request Hold

Release a held signature request to send it to signers.

Remove User from Template

Tool to remove an account's access to a template.

Send Signature Request

Tool to create and send a new signature request with documents.

Send Request Reminder

Sends an email reminder to a signer about a pending signature request.

Update Dropbox Sign Account

Tool to update Dropbox Sign account properties and settings.

Update API App

Tool to update an existing API App in Dropbox Sign.

Update Signature Request

Updates the email address and/or name for a specific signer on a signature request.

Update Template Files

Tool to update files for an existing template.

Verify Dropbox Sign Account

Tool to verify whether a Dropbox Sign account exists for the given email.

FAQ

Frequently asked questions

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

Yes, you can. Pydantic AI 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 Dropbox sign tools.

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

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