How to integrate Clientary MCP with Pydantic AI

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Introduction

This guide walks you through connecting Clientary to Pydantic AI using the Composio tool router. By the end, you'll have a working Clientary agent that can create new invoice for a client, list all active projects this month, send payment reminder to overdue clients through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Clientary account through Composio's Clientary 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:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Clientary
  • 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 Clientary 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 Clientary MCP server, and what's possible with it?

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

Supported Tools & Triggers

Tools
Create ClientTool to create a new client record in Clientary.
Create ContactTool to create a new contact within a specified client.
Create ExpenseTool to create a new expense record in Clientary to track expenditures within your account.
Create LeadTool to create a new lead record in Clientary.
Create ProjectTool to create a new project in Clientary with name and rate.
Create TaskTool to create a new task in Clientary.
Delete ClientTool to remove a client and all associated projects, invoices, estimates, and contacts.
Delete LeadTool to permanently delete a lead and all associated Estimates and Contacts.
Delete PaymentTool to remove an existing payment from an invoice.
Delete Payment ProfileTool to remove a specific payment profile from a client's account.
Delete Recurring ScheduleTool to remove a recurring schedule by its identifier.
Get ClientTool to fetch details for a specific client using its ID.
Get ContactTool to retrieve a single contact by its ID.
Get EstimateTool to retrieve details for a single estimate by ID.
Get ExpenseTool to retrieve details for a single expense record in Clientary.
Get Hour EntryTool to obtain details about a specific time entry in Clientary.
Get InvoiceTool to retrieve detailed information for a specific invoice by ID.
Get LeadTool to retrieve a single lead by its ID.
Get ProjectTool to retrieve a single project by its identifier.
Get StaffTool to retrieve a single staff member by their ID.
Get TaskTool to retrieve a specific task by its ID.
List Client ContactsTool to retrieve all contacts for a specific client with pagination support.
List Client ExpensesTool to retrieve all expenses for a specific client within an optional date range.
List Client InvoicesTool to retrieve all invoices for a specific client with pagination support (30 results per page).
List Client ProjectsTool to retrieve all projects associated with a specific client with pagination support (10 results per page).
List ClientsTool to retrieve all clients with pagination support (10 results per page).
List ExpensesTool to retrieve expenses by date range (defaults to current fiscal year).
List LeadsTool to retrieve all leads with pagination support.
List PaymentsTool to retrieve all payments with pagination support (30 results per page).
List Project EstimatesTool to retrieve estimates scoped to a particular project with pagination support (30 results per page).
List Project ExpensesTool to retrieve all expenses for a specific project within an optional date range.
List Project HoursTool to retrieve all time tracking entries logged against a specific project.
List Project InvoicesTool to retrieve all invoices linked to a specific project with pagination support (30 results per page).
List ProjectsTool to retrieve all projects with pagination support (10 results per page).
List StaffTool to retrieve all staff members for an account.
List TasksTool to retrieve all tasks with pagination support (50 results per page).
Send Invoice MessageTool to send an invoice message to recipients via email.
Update ClientTool to update an existing client record in Clientary with partial or complete field modifications.
Update ExpenseTool to update an existing expense record in Clientary with partial or complete field modifications.
Update Hour EntryTool to modify an existing time entry in Clientary with partial or complete field updates.
Update ProjectTool to update an existing project in Clientary with partial or complete field modifications.
Update TaskTool to update an existing task in Clientary with partial or complete field modifications.

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, make sure you have:
  • Python 3.9 or higher
  • A Composio account with an active 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

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

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

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

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 Clientary
  • MCPServerStreamableHTTP connects to the Clientary MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant

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 Clientary
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["clientary"],
    )
    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 Clientary 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

Initialize the Pydantic AI Agent

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

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 Clientary.\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
  • Clientary API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns

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 Clientary 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 Clientary
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["clientary"],
    )
    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
    clientary_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[clientary_mcp],
        instructions=(
            "You are a Clientary assistant. Use Clientary 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 Clientary.\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 Clientary through Composio's Tool Router. With this setup, your agent can perform real Clientary 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 + Clientary for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.

How to build Clientary MCP Agent with another framework

FAQ

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

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

Can I use Tool Router MCP with Pydantic AI?

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 Clientary tools.

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

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

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