How to integrate Esignatures io MCP with LangChain

This guide walks you through connecting Esignatures io to LangChain using the Composio tool router. By the end, you'll have a working Esignatures io agent that can send a contract to a new client for signature, list all available contract templates, withdraw a contract that hasn't been signed through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Esignatures io account through Composio's Esignatures io MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Esignatures io is an e-signature platform for sending and signing contracts online. Its mobile-friendly experience streamlines contract management and signing workflows.

17 Tools

Introduction

This guide walks you through connecting Esignatures io to LangChain using the Composio tool router. By the end, you'll have a working Esignatures io agent that can send a contract to a new client for signature, list all available contract templates, withdraw a contract that hasn't been signed through natural language commands.

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

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

Also integrate Esignatures io 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 Esignatures io project to Composio
  • Create a Tool Router MCP session for Esignatures io
  • Initialize an MCP client and retrieve Esignatures io tools
  • Build a LangChain agent that can interact with Esignatures io
  • 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 Esignatures io MCP server, and what's possible with it?

The Esignatures io MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Esignatures io account. It provides structured and secure access to your contract management tools, so your agent can create contracts, manage templates, handle signer profiles, and control contract workflows seamlessly on your behalf.

  • Automated contract creation and sending: Instantly generate and send new contracts for signature using pre-built templates and custom signer details.
  • Template management and organization: Allow your agent to create, retrieve, list, and delete contract templates for easy document standardization and reuse.
  • Signer profile creation: Effortlessly add new signers to your account, making it simple to initiate or update signature requests as needed.
  • Contract withdrawal and workflow control: Instantly withdraw contracts that should no longer be signed, preventing further action on outdated or incorrect documents.

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 Esignatures io 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 Esignatures io 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: ['esignatures_io']
    }
);

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

Configure the agent with the MCP URL

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

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

Add Template Collaborator

Tool to grant editing access to a template with optional email invitation.

Copy Template

Tool to duplicate an existing template with optional customization.

Create Contract

Tool to create a new contract using a specified template and signer details.

Create Signer

Add a signer to an existing contract/signature request.

Create Template

Tool to create a new template.

Delete Signer

Tool to remove a signer from a contract.

Delete Template

Tool to delete a specific template by its ID.

Generate Contract PDF Preview

Tool to generate a PDF preview of a contract and receive a webhook notification with a download URL.

Get Contract

Tool to retrieve details of a specific contract by its ID.

Get Template

Tool to retrieve details of a specific template by its ID.

List Template Collaborators

Tool to retrieve all collaborators with editing access to a template.

List Templates

Tool to retrieve a list of all templates.

Remove Template Collaborator

Tool to revoke a collaborator's template editing permissions.

Send Contract to Signer

Tool to send or resend a contract signature request to a specific signer via their configured communication channel.

Update Signer

Tool to update contact details of an existing signer on a contract.

Update Template

Tool to update an existing template's content, title, or labels.

Withdraw Contract

Tool to withdraw a contract by its ID.

FRAMEWORKS

How to build Esignatures io MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Esignatures io MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Esignatures io MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Esignatures io MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Esignatures io MCP with Claude Cowork

Codex logo

Codex

Use Esignatures io MCP with Codex

OpenClaw logo

OpenClaw

Use Esignatures io MCP with OpenClaw

Hermes logo

Hermes

Use Esignatures io MCP with Hermes

CLI logo

CLI

Use Esignatures io MCP with CLI

Google ADK logo

Google ADK

Use Esignatures io MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Esignatures io MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Esignatures io MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Esignatures io MCP with LlamaIndex

CrewAI logo

CrewAI

Use Esignatures io MCP with CrewAI

FAQ

Frequently asked questions

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

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

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