SIGN UPLOG IN
X (Twitter)LinkedInGitHubDiscordYouTube

How to integrate Alchemy MCP with LangChain

Connect LangChain to Alchemy MCP. Show all nfts owned by this wallet, get recent sales for a specific nft collection, and more using natural language, with authentication handled for you.

Get started for freeGet a demo
Alchemy logoAlchemy
Api Key

Alchemy is a blockchain development platform offering APIs and tools for Ethereum apps. It simplifies building and scaling Web3 projects with robust infrastructure.

36 Tools

Introduction

This guide walks you through connecting Alchemy to LangChain using the Composio tool router. By the end, you'll have a working Alchemy agent that can fetch NFTs and metadata by owner or collection, check token balances and prices, view transaction history, and detect spam contracts through natural language commands.

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

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

Also integrate Alchemy with

Claude CodeClaude CoworkOpenAI Agents SDKClaude Agent SDKCodexOpenClawHermesAtomic AgentGoogle ADKVercel AI SDKMastra AILlamaIndexCrewAIPydantic AIAutoGen

TL;DR

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

The Alchemy MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Alchemy account. It provides structured and secure access to blockchain portfolio, token, transaction, and NFT data, so your agent can inspect wallet balances, retrieve transaction history, check token prices, analyze NFTs, and identify spam contracts on your behalf.

  • Wallet and token tracking: Have your agent fetch native and fungible token holdings for wallet addresses across supported blockchain networks.
  • Token pricing and metadata: Let the agent retrieve current or historical token prices and look up details such as names, symbols, decimals, and logos.
  • Transaction history: Direct your agent to review transaction activity for wallet addresses across supported networks.
  • NFT portfolio and market research: Instruct your agent to inspect owned NFTs, collection and contract metadata, NFT sales, marketplace floor prices, and individual NFT attributes.
  • Spam contract detection: Have your agent check whether an NFT contract is marked as spam by Alchemy.

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 Alchemy 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 Alchemy 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: ['alchemy']
    }
);

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

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "alchemy-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 Alchemy MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • getTools() retrieves all available Alchemy 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 Alchemy 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 Alchemy 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: ['alchemy']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "alchemy-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 Alchemy 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 Alchemy 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 Alchemy action and event your agent gets out of the box.

Compute NFT Rarity

Tool to compute the rarity of each attribute for a specific NFT based on its collection.

Get NFT Collection Metadata

Get NFT collection metadata by OpenSea slug on Ethereum mainnet, including available name, description, social links, and floor price, without requiring a contract address.

Get Collections for Owner

Tool to retrieve all NFT collections held by a specified owner address.

Get Contract Metadata Batch V3

Retrieve metadata for multiple Ethereum mainnet NFT contracts in a single batch request.

Get Contract Metadata V3

Get metadata for an Ethereum mainnet NFT contract, including available name, symbol, total supply, token type, deployer, deployment block, and OpenSea collection details.

Get Contracts for Owner (NFT API v3)

Retrieve NFT contracts from which an Ethereum mainnet wallet holds tokens, with available contract metadata, spam classification, and OpenSea metadata.

Get NFT Floor Price

Get Ethereum mainnet NFT collection floor prices from OpenSea and LooksRare, including available price, currency, collection URL, and retrieval timestamp.

Get Historical Token Prices

Retrieves historical price data for a token over a specified time range with configurable intervals.

Get NFT Contracts By Address

Tool to retrieve NFT contracts associated with one or more wallet addresses across multiple blockchain networks.

Get NFT Metadata

Retrieves metadata for a specific NFT on Ethereum mainnet, including available contract details, media URLs, attributes, and OpenSea data.

Get NFT Metadata Batch

Retrieves metadata for up to 100 NFTs on Ethereum mainnet in a single request, including available contract details, media URLs, attributes, and collection data.

Get NFT Sales V3

Retrieves Ethereum mainnet NFT sales through on-chain marketplaces using Alchemy's v3 API, including fees and transaction details.

Get NFTs for Collection V3

Retrieves NFTs in an Ethereum mainnet collection using an OpenSea collection slug or contract address.

Get NFTs for Contract

Retrieves NFTs for an Ethereum mainnet NFT contract, supporting ERC721 and ERC1155.

Get NFTs for Owner

Retrieves NFTs owned by an address on Ethereum mainnet, supporting ERC721 and ERC1155 tokens, optional metadata, filtering, and pagination.

Get Owners for Collection

Retrieves owner addresses for an Ethereum mainnet NFT collection contract, with optional token balances per owner and pagination.

Get Owners for Contract

Retrieves owners of NFTs in an Ethereum mainnet contract, with optional token balances and pagination.

Get NFT Owners (v3)

Retrieves owner addresses for a specific Ethereum mainnet NFT using Alchemy's v3 API.

Get Portfolio NFTs By Address

Tool to fetch NFTs owned by multiple wallet addresses across different blockchain networks.

Get Token Prices By Symbol

Tool to get current token prices by symbol (e.

Get Token Balances

This tool retrieves ERC20 token balances for a specified Ethereum address.

Get Token Balances By Address

Tool to get token balances for wallet addresses across multiple networks using Alchemy's Portfolio API.

Get Token Metadata

Retrieves Ethereum mainnet ERC-20 token metadata, including available name, symbol, decimals, and logo URL, for display and token amount conversion.

Get Token Prices By Address

Retrieves current token prices by contract address and network from decentralized exchanges (DEXes).

Get Tokens By Address

Tool to fetch fungible tokens (native, ERC-20, SPL) for multiple wallet addresses across networks.

Get Transaction Count

Retrieves an Ethereum mainnet address's transaction count (nonce) at a specified block tag or hexadecimal block number using eth_getTransactionCount.

Get Transactions History By Address

Retrieves transaction history for one wallet address across up to two networks using Alchemy's Data API.

Invalidate NFT Contract Cache

Tool to invalidate the cached metadata for an NFT contract.

Check If NFT Is Airdrop

Tool to check if a specific NFT token is marked as an airdrop.

Check If NFT Is Airdrop

Check whether a specified NFT is marked as an airdrop using its contract address and token ID on Ethereum mainnet.

Check Collection Ownership

Tool to check if a wallet address owns any token from a specific NFT collection.

Check NFT Holder Status

Tool to check if a wallet address holds any NFTs from a specific contract.

Check if Contract is Spam

Tool to check if an NFT contract is marked as spam by Alchemy.

Check if Contract is Spam (V3)

Tool to determine if a specific NFT contract is marked as spam by Alchemy.

Search NFT Contract Metadata

Search Ethereum mainnet NFT contract metadata by keywords to find collections.

Summarize NFT Attributes

Retrieves a summary of NFT attributes for an Ethereum mainnet collection, including trait value counts.

FRAMEWORKS

How to build Alchemy MCP Agent with another framework

Claude Code logo

Claude Code

Use Alchemy MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Alchemy MCP with Claude Cowork

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Alchemy MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Alchemy MCP with Claude Agent SDK

Codex logo

Codex

Use Alchemy MCP with Codex

OpenClaw logo

OpenClaw

Use Alchemy MCP with OpenClaw

Hermes logo

Hermes

Use Alchemy MCP with Hermes

Atomic Agent logo

Atomic Agent

Use Alchemy MCP with Atomic Agent

Google ADK logo

Google ADK

Use Alchemy MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Alchemy MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Alchemy MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Alchemy MCP with LlamaIndex

CrewAI logo

CrewAI

Use Alchemy MCP with CrewAI

Pydantic AI logo

Pydantic AI

Use Alchemy MCP with Pydantic AI

AutoGen logo

AutoGen

Use Alchemy MCP with AutoGen

FAQ

Frequently asked questions

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

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

Start with Alchemy.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Alchemy tool your agent needs.Free to start.

Start building