How to integrate HTML/CSS to Image MCP with LangChain

This guide walks you through connecting HTML/CSS to Image to LangChain using the Composio tool router. By the end, you'll have a working HTML/CSS to Image agent that can render html as images, create images from templates, transform images, manage templates, and track usage through natural language commands. This guide will help you understand how to give your LangChain agent real control over a HTML/CSS to Image account through Composio's HTML/CSS to Image MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Api Key

HTML/CSS to Image is an API for converting HTML, CSS, URLs, and templates into images and PDFs. Use it to generate clean visual assets, screenshots, and documents without running browser infrastructure.

10 Tools

Introduction

This guide walks you through connecting HTML/CSS to Image to LangChain using the Composio tool router. By the end, you'll have a working HTML/CSS to Image agent that can render html as images, create images from templates, transform images, manage templates, and track usage through natural language commands.

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

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

Also integrate HTML/CSS to Image with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

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

The HTML/CSS to Image MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your HTML/CSS to Image account. It provides structured and secure access to your image generation, reusable templates, generated files, and usage data, so your agent can create images, render templates, transform files, manage templates, and monitor usage on your behalf.

  • HTML and webpage rendering: Have your agent turn HTML and CSS or public web pages into hosted images, including protected pages that require request headers.
  • Batch image creation: Direct your agent to generate up to 25 images at once from HTML, CSS, or web pages using shared or image-specific settings.
  • Reusable template management: Let the agent create Handlebars templates, list your existing templates, and update them with new HTML, CSS, or render settings.
  • Image retrieval and transformation: Instruct your agent to download generated images, convert their format, resize them, crop them, or permanently delete files you no longer need.
  • Account usage tracking: Have your agent review recent hourly, daily, monthly, and billing-period image usage for your connected account.

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 step10 STEPS
1

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
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

npm install @composio/langchain @langchain/core @langchain/openai @langchain/mcp-adapters 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/core is the core agent framework
  • dotenv/config loads environment variables
4

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
5

Import dependencies

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

dotenv.config();
What's happening:
  • We're importing LangChain's MCP adapter and Composio SDK
  • The dotenv/config import loads environment variables from your .env file
  • This setup prepares the foundation for connecting LangChain with HTML/CSS to Image functionality through MCP
6

Initialize Composio client

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });
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 HTML/CSS to Image tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding
7

Create a Tool Router session

const session = await composio.create(
    userId as string,
    {
        toolkits: ['htmlcss_to_image']
    }
);

const url = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to HTML/CSS to Image 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 HTML/CSS to Image tools as needed
8

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "htmlcss_to_image-agent": {
        transport: "http",
        url: url,
        headers: {
            "x-api-key": process.env.COMPOSIO_API_KEY
        }
    }
});

const tools = await client.getTools();

const agent = createAgent({ model: "gpt-5", tools });
What's happening:
  • We're creating a MultiServerMCPClient that connects to our HTML/CSS to Image MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • getTools() retrieves all available HTML/CSS to Image tools that the agent can use
  • We're creating a LangChain agent using the GPT-5 model
9

Set up interactive chat interface

let conversationHistory: any[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log("Ask any HTML/CSS to Image related question or task to the agent.\n");

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
});

rl.prompt();

rl.on('line', async (userInput: string) => {
    const trimmedInput = userInput.trim();

    if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
        console.log("\nGoodbye!");
        rl.close();
        process.exit(0);
    }

    if (!trimmedInput) {
        rl.prompt();
        return;
    }

    conversationHistory.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    const response = await agent.invoke({ messages: conversationHistory });
    conversationHistory = response.messages;

    const finalResponse = response.messages[response.messages.length - 1]?.content;
    console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\n👋 Session ended.');
        process.exit(0);
    });
What's happening:
  • We initialize an empty conversationHistory list to maintain context across interactions
  • A readline interface is used to continuously accept 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 invoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully
10

Run the application

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});
What's happening:
  • We call the main() function to start the application

Complete Code

Here's the complete code to get you started with HTML/CSS to Image and LangChain:

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";  
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

    const session = await composio.create(
        userId as string,
        {
            toolkits: ['htmlcss_to_image']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "htmlcss_to_image-agent": {
            transport: "http",
            url: url,
            headers: {
                "x-api-key": process.env.COMPOSIO_API_KEY
            }
        }
    });
    
    const tools = await client.getTools();
  
    const agent = createAgent({ model: "gpt-5", tools });
    
    let conversationHistory: any[] = [];
    
    console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
    console.log("Ask any HTML/CSS to Image related question or task to the agent.\n");
    
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
        prompt: 'You: '
    });

    rl.prompt();

    rl.on('line', async (userInput: string) => {
        const trimmedInput = userInput.trim();
        
        if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
            console.log("\nGoodbye!");
            rl.close();
            process.exit(0);
        }
        
        if (!trimmedInput) {
            rl.prompt();
            return;
        }
        
        conversationHistory.push({ role: "user", content: trimmedInput });
        console.log("\nAgent is thinking...\n");
        
        const response = await agent.invoke({ messages: conversationHistory });
        conversationHistory = response.messages;
        
        const finalResponse = response.messages[response.messages.length - 1]?.content;
        console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\nSession ended.');
        process.exit(0);
    });
}

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});

Conclusion

You've successfully built a LangChain agent that can interact with HTML/CSS to Image 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.
TOOLS

Supported Tools

Every HTML/CSS to Image action and event your agent gets out of the box.

Create Image

Create a hosted image from HTML/CSS or an internet-reachable webpage, including authenticated pages using request headers.

Create Image from Template

Create an image from a reusable template using the latest version or an explicitly selected version.

Create Images Batch

Create 1 to 25 hosted images from HTML/CSS or internet-reachable webpages in one request, including authenticated pages using shared or per-image headers.

Create Template

Create a reusable Handlebars HTML/CSS image template.

Delete Image

Permanently delete one generated image and clear its HCTI CDN cache.

Delete Images Batch

Permanently delete multiple generated images and clear their HCTI CDN caches.

Get or Transform Image

Download a generated image by ID, optionally converting its format, resizing it, or cropping it.

Get Usage

Return recent hourly, daily, monthly, and billing-period image usage for the connected account.

List Templates

List reusable image templates owned by the connected account, including their current version, source, and render settings.

Update Template

Create a new version of an existing template using replacement Handlebars HTML and optional CSS or render settings.

FRAMEWORKS

How to build HTML/CSS to Image MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use HTML/CSS to Image MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use HTML/CSS to Image MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use HTML/CSS to Image MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use HTML/CSS to Image MCP with Claude Cowork

Codex logo

Codex

Use HTML/CSS to Image MCP with Codex

OpenClaw logo

OpenClaw

Use HTML/CSS to Image MCP with OpenClaw

Hermes logo

Hermes

Use HTML/CSS to Image MCP with Hermes

CLI logo

CLI

Use HTML/CSS to Image MCP with CLI

Google ADK logo

Google ADK

Use HTML/CSS to Image MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use HTML/CSS to Image MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use HTML/CSS to Image MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use HTML/CSS to Image MCP with LlamaIndex

CrewAI logo

CrewAI

Use HTML/CSS to Image MCP with CrewAI

FAQ

Frequently asked questions

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

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 HTML/CSS to Image tools.

Yes, absolutely. You can configure which HTML/CSS to Image 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 HTML/CSS to Image data and credentials are handled as safely as possible.

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