How to integrate Neon MCP with LangChain

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Introduction

This guide walks you through connecting Neon to LangChain using the Composio tool router. By the end, you'll have a working Neon agent that can create a new neon project with autoscaling, add a developer's email permission to a project, spin up a new branch database for testing, generate an api key limited to a project through natural language commands.

This guide will help you understand how to give your LangChain agent real control over a Neon account through Composio's Neon 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:
  • Get and set up your OpenAI and Composio API keys
  • Connect your Neon project to Composio
  • Create a Tool Router MCP session for Neon
  • Initialize an MCP client and retrieve Neon tools
  • Build a LangChain agent that can interact with Neon
  • Set up an interactive chat interface for testing

What is LangChain?

LangChain is a framework for developing applications powered by language models. It provides tools and abstractions for building agents that can reason, use tools, and maintain conversation context.

Key features include:

  • Agent Framework: Build agents that can use tools and make decisions
  • MCP Integration: Connect to external services through Model Context Protocol adapters
  • Memory Management: Maintain conversation history across interactions
  • Multi-Provider Support: Works with OpenAI, Anthropic, and other LLM providers

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

The Neon MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Neon account. It provides structured and secure access to your serverless Postgres databases and project infrastructure, so your agent can perform actions like managing projects, configuring authentication, creating branches, and automating database operations on your behalf.

  • Project management and insights: Retrieve detailed information about specific Neon projects, including configurations, workflows, and current status for monitoring or troubleshooting.
  • Automated role and permission setup: Grant email-based permissions, add new roles to branches, and streamline access control across your projects with granular, automated adjustments.
  • Seamless API key and authentication management: Create new API keys for organizations or projects, manage authentication flows, and securely handle access credentials for integrations.
  • Database and branch orchestration: Spin up new Postgres databases within branches, create and configure compute endpoints, and automate the creation of development, testing, or isolated environments as needed.
  • Custom project provisioning: Launch new Neon projects with advanced quota, resource, and networking settings—tailored to your application's requirements and operational best practices.

Supported Tools & Triggers

Tools
Access project details by idRetrieves detailed information about a specific project within the neon b2b saas integration platform.
Add new jwks to project endpointAdds a new json web key set (jwks) to a specific endpoint of a project in the neon b2b saas integration platform.
Add project email permissionAdds permissions for a specified email address to a particular project within the neon b2b saas integration platform.
Add role to branchCreates a new role within a specific branch of a project in the neon b2b saas integration platform.
Create api key for organizationCreates a new api key for the specified organization, with optional project-specific access limitations.
Create branch databaseCreates a new database within a specified project and branch in the neon platform.
Create compute endpointCreates a new compute endpoint for a specified branch within a neon project.
Create new api keyCreates a new api key for accessing the neon b2b saas integration platform.
Create new project branchCreates a new branch in a neon project with optional compute endpoints.
Create project with quota and settingsCreates a new neon project with specified configuration settings.
Create vpc endpoint labelUpdates the label of a specific vpc endpoint within a project in the neon b2b saas integration platform.
Create vpc endpoint with labelUpdates the label of a specific vpc endpoint within an organization's virtual private cloud (vpc) in a particular aws region.
Delete api key by idDeletes a specific api key from the neon platform.
Delete database from branchDeletes a specific database from a designated branch within a project in the neon platform.
Delete organization api keyDeletes a specific api key associated with an organization in the neon platform.
Delete organization memberRemoves a specific member from an organization within the neon b2b saas integration platform.
Delete project branch by idDeletes a specific branch within a project in the neon b2b saas integration platform.
Delete project branch roleDeletes a specific role from a branch within a project in the neon b2b saas integration platform.
Delete project by idDeletes a specific project from the neon b2b saas integration platform.
Delete project endpointDeletes a specific endpoint within a neon project.
Delete project jwks by idDeletes a specific json web key set (jwks) associated with a given project in the neon b2b saas integration platform.
Delete project permissionDeletes a specific permission associated with a project in the neon b2b saas integration platform.
Delete vpc endpoint by idsDeletes a specific vpc endpoint within a given organization and region in the neon b2b saas integration platform.
Delete vpc endpoint by project idDeletes a specific vpc endpoint within a designated project in the neon platform.
Fetch database for branchRetrieves a list of databases associated with a specific project and branch in the neon platform.
Fetch organization members by idRetrieves a list of all members associated with a specific organization in the neon b2b saas integration platform.
Fetch vpcendpoint details by idRetrieves detailed information about a specific vpc endpoint within an organization's infrastructure in a particular aws region.
Get branches for projectRetrieves a list of branches associated with a specific project in the neon b2b saas integration platform.
Get branch roles for projectRetrieves the roles associated with a specific branch within a project in the neon b2b saas integration platform.
Get consumption history projectsRetrieves the consumption history for specified projects within the neon platform.
Get current user informationRetrieves the profile information for the currently authenticated user.
Get organization api keysRetrieves a list of all api keys associated with a specific organization in the neon b2b saas integration platform.
Get project branchesRetrieves detailed information about a specific branch within a neon project.
Get project branch roleRetrieves detailed information about a specific role within a particular branch of a neon project.
Get project connection uriRetrieves the connection uri for a specified project within the neon b2b saas integration platform.
Get project endpoint informationRetrieves a list of all endpoints associated with a specific project in the neon b2b saas integration platform.
Get project operation by idRetrieves detailed information about a specific operation within a project in the neon b2b saas integration platform.
Get schema for project branchRetrieves the schema definition for a specific branch within a project in the neon b2b saas integration platform.
Get user organizationsRetrieves a list of organizations associated with the currently authenticated user in the neon platform.
Get vpc region endpointsRetrieves a list of vpc endpoints for a specified organization within a particular aws region.
List api keysRetrieves a list of api keys associated with the authenticated user's neon account.
List shared projectsRetrieves a list of shared projects accessible to the authenticated user within the neon b2b saas integration platform.
Modify branch details in projectUpdates the details of a specific branch within a project in the neon platform.
Patch branch database informationUpdates the properties of a specific database within a project branch in the neon platform.
Reset role password for branchResets the password for a specific role within a project branch in the neon b2b saas integration platform.
Restart project endpointRestarts a specific endpoint within a project in the neon b2b saas integration platform.
Restore project branchThis endpoint restores a branch to a specific state or point in time.
Retrieve account consumption historyRetrieves the consumption history for a specified account within the neon platform.
Retrieve all regionsRetrieves a list of available geographic regions supported by the neon b2b saas integration platform.
Retrieve branch database detailsRetrieves detailed information about a specific database within a neon project and branch.
Retrieve branch endpointsRetrieves a list of endpoints associated with a specific branch of a project in the neon platform.
Retrieve jwks for projectRetrieves the json web key set (jwks) for a specified project.
Retrieve organization by idRetrieves detailed information about a specific organization within the neon platform.
Retrieve organization invitationsRetrieves a list of all pending invitations for a specified organization.
Retrieve organization member infoRetrieves detailed information about a specific member within an organization in the neon b2b saas integration platform.
Retrieve project endpoint detailsRetrieves detailed information about a specific endpoint within a project in the neon b2b saas integration platform.
Retrieve project operationsRetrieves a list of operations associated with a specific project in the neon b2b saas integration platform.
Retrieve project permissionsRetrieves the current permissions settings for a specific project within the neon b2b saas integration platform.
Retrieve projects listRetrieves a list of all neon projects associated with the authenticated user's account.
Retrieve vpc endpoints for projectRetrieves a list of vpc (virtual private cloud) endpoints associated with a specific project in the neon b2b saas integration platform.
Reveal role password in branchReveals the password for a specific role within a branch of a neon project.
Send organization invitationsCreates and sends invitations to join an organization in the neon b2b saas integration platform.
Set branch as defaultSets a specified branch as the default branch for a given project in neon.
Start endpoint for projectInitiates a specific process or workflow associated with a particular endpoint within a project in the neon b2b saas integration platform.
Suspend project endpoint by idSuspends a specific endpoint within a project in the neon b2b saas integration platform.
Transfer user projects to organizationTransfers multiple projects from the authenticated user's personal account to a specified organization within the neon b2b saas integration platform.
Update organization member roleUpdates the role of a specific member within an organization in the neon b2b saas integration platform.
Update project compute endpoint settingsUpdates the configuration of a specific compute endpoint within a neon project.
Update project settings by idUpdates the configuration and settings of a specific neon project.

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 this tutorial, make sure you have:
  • Python 3.10 or higher installed on your system
  • A Composio account with an API key
  • An OpenAI 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

pip install composio-langchain langchain-mcp-adapters langchain python-dotenv

Install the required packages for LangChain with MCP support.

What's happening:

  • composio-langchain provides Composio integration for LangChain
  • langchain-mcp-adapters enables MCP client connections
  • langchain is the core agent framework
  • python-dotenv loads environment variables

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_composio_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio's API
  • COMPOSIO_USER_ID identifies the user for session management
  • OPENAI_API_KEY enables access to OpenAI's language models

Import dependencies

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()
What's happening:
  • We're importing LangChain's MCP adapter and Composio SDK
  • The dotenv import loads environment variables from your .env file
  • This setup prepares the foundation for connecting LangChain with Neon functionality through MCP

Initialize Composio client

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))

    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
What's happening:
  • We're loading the COMPOSIO_API_KEY from environment variables and validating it exists
  • Creating a Composio instance that will manage our connection to Neon tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

# Create Tool Router session for Neon
session = composio.create(
    user_id=os.getenv("COMPOSIO_USER_ID"),
    toolkits=['neon']
)

url = session.mcp.url
What's happening:
  • We're creating a Tool Router session that gives your agent access to Neon 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
  • This approach allows the agent to dynamically load and use Neon tools as needed

Configure the agent with the MCP URL

client = MultiServerMCPClient({
    "neon-agent": {
        "transport": "streamable_http",
        "url": session.mcp.url,
        "headers": {
            "x-api-key": os.getenv("COMPOSIO_API_KEY")
        }
    }
})

tools = await client.get_tools()

agent = create_agent("gpt-5", tools)
What's happening:
  • We're creating a MultiServerMCPClient that connects to our Neon MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • get_tools() retrieves all available Neon tools that the agent can use
  • We're creating a LangChain agent using the GPT-5 model

Set up interactive chat interface

conversation_history = []

print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
print("Ask any Neon related question or task to the agent.\n")

while True:
    user_input = input("You: ").strip()

    if user_input.lower() in ['exit', 'quit', 'bye']:
        print("\nGoodbye!")
        break

    if not user_input:
        continue

    conversation_history.append({"role": "user", "content": user_input})
    print("\nAgent is thinking...\n")

    response = await agent.ainvoke({"messages": conversation_history})
    conversation_history = response['messages']
    final_response = response['messages'][-1].content
    print(f"Agent: {final_response}\n")
What's happening:
  • We initialize an empty conversation_history list to maintain context across interactions
  • A while loop continuously accepts user input from the command line
  • When a user types a message, it's added to the conversation history and sent to the agent
  • The agent processes the request using the ainvoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully

Run the application

if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • We call the main() function using asyncio.run() to start the application

Complete Code

Here's the complete code to get you started with Neon and LangChain:

from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain.agents import create_agent
from dotenv import load_dotenv
from composio import Composio
import asyncio
import os

load_dotenv()

async def main():
    composio = Composio(api_key=os.getenv("COMPOSIO_API_KEY"))
    
    if not os.getenv("COMPOSIO_API_KEY"):
        raise ValueError("COMPOSIO_API_KEY is not set")
    if not os.getenv("COMPOSIO_USER_ID"):
        raise ValueError("COMPOSIO_USER_ID is not set")
    
    session = composio.create(
        user_id=os.getenv("COMPOSIO_USER_ID"),
        toolkits=['neon']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "neon-agent": {
            "transport": "streamable_http",
            "url": url,
            "headers": {
                "x-api-key": os.getenv("COMPOSIO_API_KEY")
            }
        }
    })
    
    tools = await client.get_tools()
  
    agent = create_agent("gpt-5", tools)
    
    conversation_history = []
    
    print("Chat started! Type 'exit' or 'quit' to end the conversation.\n")
    print("Ask any Neon related question or task to the agent.\n")
    
    while True:
        user_input = input("You: ").strip()
        
        if user_input.lower() in ['exit', 'quit', 'bye']:
            print("\nGoodbye!")
            break
        
        if not user_input:
            continue
        
        conversation_history.append({"role": "user", "content": user_input})
        print("\nAgent is thinking...\n")
        
        response = await agent.ainvoke({"messages": conversation_history})
        conversation_history = response['messages']
        final_response = response['messages'][-1].content
        print(f"Agent: {final_response}\n")

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

Conclusion

You've successfully built a LangChain agent that can interact with Neon through Composio's Tool Router.

Key features of this implementation:

  • Dynamic tool loading through Composio's Tool Router
  • Conversation history maintenance for context-aware responses
  • Async Python provides clean, efficient execution of agent workflows
You can extend this further by adding error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.

How to build Neon MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Neon MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Neon MCP with Claude Agent SDK

Google ADK

Google ADK

Use Neon MCP with Google ADK

Vercel AI SDK

Vercel AI SDK

Use Neon MCP with Vercel AI SDK

Mastra AI

Mastra AI

Use Neon MCP with Mastra AI

LlamaIndex

LlamaIndex

Use Neon MCP with LlamaIndex

CrewAI

CrewAI

Use Neon MCP with CrewAI

FAQ

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

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

Can I use Tool Router MCP with LangChain?

Yes, you can. LangChain 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 Neon tools.

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

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

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