How to integrate Documenso MCP with Pydantic AI

This guide walks you through connecting Documenso to Pydantic AI using the Composio tool router. By the end, you'll have a working Documenso agent that can send a contract to client for signature, download the latest signed nda document, list all templates for onboarding paperwork through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Documenso account through Composio's Documenso MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

Documenso logoDocumenso
Api Key

Documenso is an open-source platform for digital document signing and management. It streamlines sending, tracking, and signing paperwork online—no more manual signatures or printing.

77 Tools

Introduction

This guide walks you through connecting Documenso to Pydantic AI using the Composio tool router. By the end, you'll have a working Documenso agent that can send a contract to client for signature, download the latest signed nda document, list all templates for onboarding paperwork through natural language commands.

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

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

Also integrate Documenso with

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 Documenso
  • 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 Documenso 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 Documenso MCP server, and what's possible with it?

The Documenso MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Documenso account. It provides structured and secure access to your electronic signature workflows, so your agent can create documents, distribute them for signing, manage templates, and download signed files automatically on your behalf.

  • Automated document creation and duplication: Prompt your agent to generate new documents or make exact copies of existing ones for rapid workflow setup.
  • Seamless document distribution for signatures: Let your agent send documents to one or more recipients, kicking off secure e-signature flows without manual intervention.
  • Template management and retrieval: Ask your agent to list, fetch, or delete document templates, keeping your signing processes organized and up-to-date.
  • Download and access signed documents: Have your agent retrieve finalized, signed PDFs automatically for seamless archiving or sharing.
  • Streamlined document organization: Direct your agent to move documents between personal and team spaces, or remove unnecessary fields to keep everything tidy and current.

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 Documenso
  • 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 Documenso
  • MCPServerStreamableHTTP connects to the Documenso 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 Documenso
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["documenso"],
    )
    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 Documenso 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
documenso_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[documenso_mcp],
    instructions=(
        "You are a Documenso assistant. Use Documenso tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Documenso endpoint
  • The agent uses GPT-5 to interpret user commands and perform Documenso 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 Documenso.\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
  • Documenso 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 Documenso 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 Documenso
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["documenso"],
    )
    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
    documenso_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[documenso_mcp],
        instructions=(
            "You are a Documenso assistant. Use Documenso 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 Documenso.\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 Documenso through Composio's Tool Router. With this setup, your agent can perform real Documenso 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 + Documenso 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 Documenso action and event your agent gets out of the box.

Create Document Beta

Tool to create a new document using the beta endpoint that returns a presigned URL for file upload.

Create Document Field

Tool to create a single field for a document.

Create Document Fields (Bulk)

Tool to create multiple fields on a document in a single operation.

Create Document Recipient

Tool to create a single recipient for a document.

Create Document Recipients Bulk

Tool to create multiple recipients for a document at once.

Create Embedding Presign Token V2 Beta

Create a presign token for Documenso embedded authoring sessions.

Create Envelope

Tool to create a new envelope in Documenso.

Create Envelope Attachment

Create a new attachment for an envelope in Documenso.

Create Envelope Items Bulk

Tool to create multiple items for an envelope with optional file attachments.

Create Envelope Recipients Bulk

Tool to create multiple recipients for an envelope in bulk.

Create Folder

Create a new folder in Documenso to organize documents or templates.

Create Template Beta

Tool to create a new template using the beta endpoint that returns a presigned URL for file upload.

Create Template Field

Tool to create a single field for a template.

Create Template Fields (Bulk)

Tool to create multiple fields on a template in a single operation.

Create Template Recipient

Tool to create a single recipient for a template.

Create Template Recipients Bulk

Tool to create multiple recipients for a template at once.

Delete Document

Tool to delete a document.

Delete Document Attachment

Tool to delete an attachment from a document.

Delete Document Field

Tool to delete a single document field by ID.

Delete Document Fields

Tool to delete one or more fields from a document.

Delete Document Recipient

Tool to delete a recipient from a document.

Delete Envelope

Tool to permanently delete an envelope.

Delete Envelope Attachment

Tool to delete an attachment from an envelope.

Delete Envelope Field

Tool to delete a field from an envelope.

Delete Envelope Item

Tool to delete an item from an envelope.

Delete Envelope Recipient

Tool to delete a recipient from an envelope.

Delete Folder

Tool to permanently delete a folder.

Delete Template

Permanently delete a template by its ID.

Delete Template Direct Link

Delete a direct link for a template.

Delete Template Recipient

Tool to delete a recipient from a template.

Delete Template V2

Tool to permanently delete a template using the v2 API.

Distribute Document V2

Tool to distribute a document for signing.

Distribute Envelope

Tool to distribute an envelope to recipients for signing.

Download Envelope Item

Download an envelope item as PDF.

Download Signed Document

Download a completed/signed document as PDF.

Duplicate Document V2

Tool to duplicate a document.

Duplicate Envelope V2

Tool to duplicate an envelope with all its settings.

Duplicate Template

Tool to duplicate a template with all its settings.

Find Documents

Find documents based on search criteria with filtering and pagination.

Find Documents V2

Retrieve a paginated list of documents with optional filtering and sorting.

Find Envelopes

Tool to find envelopes based on search criteria, filters, and pagination.

Find Folders

Tool to find folders based on search criteria and filters.

Find Templates

Retrieve a paginated list of templates with optional filtering and search.

Get Document By ID

Retrieve complete information about a document by its ID.

Get Document Field

Tool to retrieve a document field by its ID.

Get Document Recipient

Tool to retrieve detailed information about a document recipient by their ID.

Get Documents By IDs

Retrieve multiple documents by their IDs in a single request.

Get Envelope Attachment

Tool to find all attachments for a specific envelope.

Get Envelope Audit Log

Tool to retrieve audit logs for an envelope.

Get Envelope By ID

Retrieve complete information about an envelope by its ID.

Get Envelope Field

Tool to fetch an envelope field by ID.

Get Envelope Recipient

Tool to retrieve detailed information about an envelope recipient by their ID.

Get Envelopes By IDs

Tool to retrieve multiple envelopes by their IDs.

Get Template By ID

Retrieve complete information about a template by its ID.

Get Template Field

Tool to fetch a template field by ID.

Get Template Recipient

Tool to retrieve detailed information about a template recipient by their ID.

Get Templates By IDs

Retrieve multiple templates by their IDs in a single request.

List Templates

Tool to list templates.

Move Document V2

Tool to move a document to a team.

Redistribute Document V2

Re-send signing request emails to specified recipients of a document.

Redistribute Envelope

Tool to redistribute an envelope to recipients who have not actioned it.

Remove Team Member V1

Remove a member from a Documenso team.

Update Document Attachment

Tool to update an existing document attachment.

Update Document Field

Tool to update a single document field's properties in Documenso v2 API.

Update Document Fields Bulk

Tool to update multiple document fields in a single operation.

Update Document Recipient V2

Tool to update a document recipient using the v2 API.

Update Document V2

Update document properties like title, visibility, and signing settings.

Update Envelope

Update envelope properties like title, visibility, and signing settings.

Update Envelope Attachment

Tool to update an existing envelope attachment.

Update Envelope Fields Bulk

Tool to update multiple envelope fields in a single request.

Update Envelope Items Bulk

Tool to update multiple envelope items in a single request.

Update Folder

Update properties of an existing folder including name, pinned status, parent folder, and visibility.

Update Template

Update template properties like title, visibility, and signing settings.

Update Template Fields Bulk

Tool to update multiple template fields in a single operation.

Update Template Recipient

Tool to update a template recipient.

Update Template Recipients Bulk

Tool to update multiple template recipients in a single API call.

Use Template (v2-beta)

Tool to create a document from a template.

FAQ

Frequently asked questions

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

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

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