How to integrate Neo4J MCP with Pydantic AI

This guide walks you through connecting Neo4J to Pydantic AI using the Composio tool router. By the end, you'll have a working Neo4J agent that can run cypher queries on customer graph, find shortest paths between accounts, create nodes for new transactions through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Neo4J account through Composio's Neo4J MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Introduction

This guide walks you through connecting Neo4J to Pydantic AI using the Composio tool router. By the end, you'll have a working Neo4J agent that can run cypher queries on customer graph, find shortest paths between accounts, create nodes for new transactions through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Neo4J account through Composio's Neo4J 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 Neo4J
  • 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 Neo4J 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 Neo4J MCP server, and what's possible with it?

The Neo4J MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Neo4J account. It provides structured and secure access to your Neo4J Aura resources, so your agent can manage database instances, handle snapshots, review projects and users, monitor Graph Data Science sessions, and configure IP filters on your behalf.

  • Aura instance management: Have your agent list, create, inspect, update, or pause Neo4J Aura instances based on your infrastructure needs.
  • Snapshot and recovery operations: Direct your agent to create snapshots, review available backups, inspect snapshot details, or restore an Aura instance from a snapshot.
  • Project and user oversight: Let the agent list Aura projects, inspect project details, review project users, or retrieve information about an organization user.
  • Graph Data Science planning: Instruct your agent to list active Graph Data Science sessions or estimate session size from node counts, relationship counts, and algorithm categories.
  • Network access and agent review: Have your agent list Aura agents, review organization IP filters, or update an existing IP filter.

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 Neo4J
  • 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 Neo4J
  • MCPServerStreamableHTTP connects to the Neo4J 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 Neo4J
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["neo4j"],
    )
    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 Neo4J 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
neo4j_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[neo4j_mcp],
    instructions=(
        "You are a Neo4J assistant. Use Neo4J tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Neo4J endpoint
  • The agent uses GPT-5 to interpret user commands and perform Neo4J 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 Neo4J.\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
  • Neo4J 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 Neo4J 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 Neo4J
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["neo4j"],
    )
    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
    neo4j_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[neo4j_mcp],
        instructions=(
            "You are a Neo4J assistant. Use Neo4J 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 Neo4J.\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 Neo4J through Composio's Tool Router. With this setup, your agent can perform real Neo4J 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 + Neo4J 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 Neo4J action and event your agent gets out of the box.

Aggregate Directors Count

Executes a directorsAggregate GraphQL query to count directors in Neo4j.

Create Neo4j Aura Instance

Creates a new Neo4j Aura instance with the specified configuration.

Create Neo4j Aura Snapshot

Create an on-demand snapshot of a Neo4j Aura instance.

Estimate GDS Session Size

Estimate the size of a new GDS (Graph Data Science) session based on node/relationship counts and algorithm categories.

Get Neo4j Aura Instance Details

Retrieves details for a specific Neo4j Aura instance using its unique instance ID.

Get Neo4j Aura Organization User

Retrieves details of a specific user in a Neo4j Aura organization.

Get Neo4j Aura Project Details

Retrieve details of a specific Neo4j Aura project (tenant).

Get Neo4j Aura Project Details (v1beta5)

Retrieve details of a specific Neo4j Aura project (tenant) using the v1beta5 API.

Get Neo4j Aura Snapshot Details

Retrieves details of a specific snapshot for a Neo4j Aura instance.

List Neo4j Aura Agents

List all agents belonging to a specific Neo4j Aura project.

List GDS Sessions

List all Graph Data Science (GDS) sessions for the authenticated Neo4j Aura account.

List Neo4j Aura Instances

Returns a list of Neo4j Aura instances.

List IP Filters

Returns a list of IP filters configured for a Neo4j Aura organization.

List Aura Projects

List all Aura projects (tenants) available to the authenticated user.

List Project Users

List all users in a specific Neo4j Aura project.

List Neo4j Aura Snapshots

Lists available snapshots for a Neo4j Aura instance.

Pause Neo4j Aura Instance

Pauses a Neo4j Aura instance.

Restore Neo4j Aura Instance from Snapshot

Restore a Neo4j Aura instance from a snapshot.

Update Neo4j Aura Instance

Updates a Neo4j Aura instance configuration.

Update Neo4j Aura Instance

Edits the configuration of a Neo4j Aura instance.

Update IP Filter

Updates an existing IP filter for a Neo4j Aura organization.

FAQ

Frequently asked questions

With a standalone Neo4J MCP server, the agents and LLMs can only access a fixed set of Neo4J tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Neo4J 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 Neo4J tools.

Yes, absolutely. You can configure which Neo4J 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 Neo4J data and credentials are handled as safely as possible.

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