How to integrate Hashnode MCP with LangChain

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Introduction

This guide walks you through connecting Hashnode to LangChain using the Composio tool router. By the end, you'll have a working Hashnode agent that can list your most recent hashnode articles, check if 'devjournal.com' domain is available, fetch popular tags for trending topics through natural language commands.

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

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

Also integrate Hashnode with

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Connect your Hashnode project to Composio
  • Create a Tool Router MCP session for Hashnode
  • Initialize an MCP client and retrieve Hashnode tools
  • Build a LangChain agent that can interact with Hashnode
  • 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 Hashnode MCP server, and what's possible with it?

The Hashnode MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Hashnode account. It provides structured and secure access to your blog and developer publication data, so your agent can fetch articles, manage publication invites, reply to comments, and explore tags or user details on your behalf.

  • Fetch and analyze articles: Let your agent retrieve single articles or lists of posts from your publications, making it easy to summarize, review, or manage your content.
  • Publication invite handling: Effortlessly accept publication invitations or view all your pending invites, streamlining the process of joining new developer teams or publications.
  • Interact with comments and replies: Have your agent add replies to existing comments, enabling automated engagement and conversation management on your posts.
  • Tag discovery and trend tracking: Easily fetch popular tags so your agent can suggest relevant topics, optimize your writing focus, or help you follow industry trends.
  • User and publication insights: Retrieve detailed profile information for any user or publication, giving your agent the context needed for personalized recommendations and content actions.

Supported Tools & Triggers

Tools
Hashnode Accept Publication InviteTool to accept a publication invitation.
Hashnode Add CommentAdd a comment to a Hashnode post.
Hashnode Add Content BlockTool to add a content block to a Hashnode documentation project.
Hashnode Add Custom MDX ComponentTool to add a custom MDX component to a Hashnode documentation project.
Hashnode: Add Documentation Project Custom DomainTool to add a custom domain to a Hashnode documentation project.
Hashnode Add ReplyTool to add a reply to an existing comment.
Hashnode: Check Custom Domain AvailabilityTool to check if a custom domain is available for your Hashnode publication.
Hashnode: Check Subdomain AvailabilityTool to check if a subdomain is available for a Hashnode publication.
Create Documentation API ReferenceTool to create a documentation API reference from an OpenAPI specification URL in a Hashnode project.
Create Documentation LinkTool to create a link within a Hashnode documentation guide.
Hashnode: Create Documentation ProjectTool to create a new documentation project on Hashnode.
Hashnode Create Documentation SectionTool to create a new documentation section in a Hashnode documentation guide.
Create Hashnode Documentation GuideTool to create a new documentation guide in a Hashnode documentation project.
Hashnode Delete Content BlockTool to delete a content block from a Hashnode documentation project.
Hashnode Delete Custom MDX ComponentTool to delete a custom MDX component from a Hashnode documentation project.
Disable Documentation Project AI SearchTool to disable AI search for a documentation project on Hashnode.
Hashnode: Fetch InvitationsFetch pending publication invitations for a Hashnode publication.
Hashnode: Fetch Popular TagsTool to fetch a paginated list of popular tags.
Fetch Publication PostsTool to fetch a paginated list of posts from a publication.
Fetch Series PostsTool to fetch posts from a series within a publication.
Fetch Single ArticleTool to fetch a single article by slug from a publication.
Fetch Stories FeedFetch a paginated feed of stories from Hashnode.
Hashnode: Fetch User DetailsTool to fetch detailed user profile information by username.
Hashnode: Follow TagsFollow specified tags to customize your content feed on Hashnode.
Generate Documentation Project Preview Authorization TokenTool to generate a JWT authorization token for previewing a documentation project.
Get Documentation ProjectTool to fetch details of a Docs by Hashnode project by ID or hostname.
Get Post by IDTool to retrieve a published post by ID from Hashnode.
Get Publication by ID or HostTool to fetch publication details by ID or hostname.
Hashnode: Get Tag DetailsTool to fetch detailed information about a tag by its slug.
Hashnode Like CommentTool to like a comment on Hashnode.
Hashnode Like PostTool to like a post on Hashnode.
Hashnode: Like ReplyTool to like a reply on Hashnode.
Hashnode: List PublicationsTool to list all publications of the authenticated user.
Hashnode: List Top CommentersTool to fetch users who have most actively participated in discussions by commenting in the last 7 days.
Hashnode: Map Documentation Project WWW RedirectTool to configure WWW redirect for a documentation project's custom domain.
Hashnode: Get Current UserRetrieves profile details of the currently authenticated Hashnode user.
Move Documentation Sidebar ItemTool to reorder documentation sidebar items within a Hashnode guide.
Publish Documentation API ReferenceTool to publish a documentation API reference in a Hashnode documentation project.
Hashnode Publish PostTool to publish a new blog post to a Hashnode publication.
Hashnode Remove CommentTool to remove a comment from a Hashnode post.
Hashnode Remove Documentation GuideTool to remove a documentation guide from a Hashnode project.
Remove Documentation ProjectTool to remove a documentation project from Hashnode.
Hashnode Remove Documentation Project Custom DomainTool to remove a custom domain from a Hashnode documentation project.
Remove Documentation Sidebar ItemTool to remove a sidebar item from a documentation guide on Hashnode.
Hashnode Remove PostTool to remove (delete) a post from Hashnode.
Hashnode Remove ReplyTool to remove a reply from a comment.
Hashnode Rename Documentation GuideTool to rename a documentation guide in a Hashnode project.
Rename Documentation Sidebar ItemTool to rename a documentation sidebar item within a Hashnode guide.
Hashnode Restore PostTool to restore a previously deleted Hashnode post.
Save Documentation Page Draft ContentTool to save draft content for a documentation page in Hashnode.
Search Posts of PublicationTool to search and retrieve posts from a specific publication based on a search query.
Subscribe to NewsletterTool to subscribe an email address to a Hashnode publication's newsletter.
Hashnode: Toggle Follow UserTool to toggle follow status for a Hashnode user.
Hashnode: Unfollow TagsUnfollow specified tags to customize your content feed on Hashnode.
Unsubscribe from NewsletterTool to unsubscribe an email address from a Hashnode publication's newsletter.
Hashnode Update CommentTool to update an existing comment on a Hashnode post.
Hashnode Update Content BlockTool to update a content block in a Hashnode documentation project.
Update Documentation AppearanceTool to update the appearance settings of a Hashnode documentation project.
Update Documentation General SettingsTool to update general settings of a Hashnode documentation project.
Update Hashnode Documentation GuideTool to update an existing documentation guide in a Hashnode project.
Hashnode: Update Documentation IntegrationsTool to update third-party integrations for a Docs by Hashnode project.
Update Documentation LinkTool to update an existing link within a Hashnode documentation guide.
Hashnode: Update Documentation Project SubdomainTool to update the subdomain of a Hashnode documentation project.
Hashnode Update Documentation SectionTool to update a section in a Hashnode documentation guide.
Hashnode Update PostTool to update an existing Hashnode post via the updatePost mutation.
Hashnode Update ReplyTool to update a reply.
Hashnode Verify Documentation Project Custom DomainTool to verify a custom domain for a Hashnode documentation project.

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

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 Hashnode 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 Hashnode tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

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

url = session.mcp.url
What's happening:
  • We're creating a Tool Router session that gives your agent access to Hashnode 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 Hashnode tools as needed

Configure the agent with the MCP URL

client = MultiServerMCPClient({
    "hashnode-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 Hashnode MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • get_tools() retrieves all available Hashnode 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 Hashnode 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 Hashnode 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=['hashnode']
    )

    url = session.mcp.url
    
    client = MultiServerMCPClient({
        "hashnode-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 Hashnode 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 Hashnode 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 Hashnode MCP Agent with another framework

FAQ

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

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

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

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

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