How to integrate eSignatures MCP with LangChain

This guide walks you through connecting eSignatures to LangChain using the Composio tool router. By the end, you'll have a working eSignatures agent that can draft contracts, send contracts for signing, add signers, manage templates, and check contract details through natural language commands. This guide will help you understand how to give your LangChain agent real control over a eSignatures account through Composio's eSignatures MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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eSignatures is an electronic signature platform for creating templates, sending contracts, and managing signers. It helps teams close agreements faster with trackable, paperless signing workflows.

28 Tools

Introduction

This guide walks you through connecting eSignatures to LangChain using the Composio tool router. By the end, you'll have a working eSignatures agent that can draft contracts, send contracts for signing, add signers, manage templates, and check contract details through natural language commands.

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

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

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

The eSignatures 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 account. It provides structured and secure access to your contract templates, contracts, signers, and signing workflows, so your agent can create and send contracts, manage signers, update content, track signing status, and organize templates on your behalf.

  • Contract creation and delivery: Have your agent create contract drafts from templates or Markdown, send them for signature, or send an existing draft when it is ready.
  • Signer management: Let the agent add, update, or remove signers from editable contracts, resend signature requests, and adjust signer contact, delivery, authentication, or redirect details.
  • Template creation and collaboration: Direct your agent to create, duplicate, rename, label, or delete reusable templates, and manage the collaborators who can edit them.
  • Contract and template editing: Instruct your agent to preview and apply exact content changes, update contract placeholder values, and review template or contract Markdown.
  • Signing workflow tracking: Have your agent check contract details, current status, signers, completed field values, and signed documents when available, or withdraw an active unsigned contract.

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 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 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']
    }
);

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

Configure the agent with the MCP URL

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

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

Add Contract Signer

Add a signer to an editable contract without automatically sending a signature request.

Add Contract Signers

Add a non-empty list of signers to an editable contract by calling the provider's singular endpoint sequentially in request order.

Add Template Collaborator

Create a name-only collaborator who can edit a template.

Create and Send Contract

Create a contract from a template or from ad-hoc Markdown and immediately send signature requests to its signers.

Create Contract Draft

Create a test or production contract draft from a template or from ad-hoc Markdown, without sending signature requests or otherwise delivering it externally.

Create Template

Create a reusable Markdown contract template.

Delete Contract Signer

Permanently remove a signer from an editable contract.

Delete Template

Permanently delete a template.

Duplicate Template

Duplicate a template with a new title plus optional placeholder replacements.

Get Contract

Get one contract's current status, details, signers, signer field values, and temporary signed-PDF URL when available.

Get Contract Content

Return the Markdown content of one contract.

Get Contract Placeholder Fields

Return the current placeholder replacements for one contract.

Get Template

Get one template's metadata, placeholder keys, and signer-field IDs.

Get Template Content

Return the Markdown content of one template.

Invite Template Collaborator

Invite a collaborator to edit a template.

List Template Collaborators

Return all collaborators who can edit one template.

List Templates

Return all templates available to the connected account.

Preview Contract Content Update

Preview the prospective Markdown from exact find-and-replace edits without mutating the contract.

Preview Template Content Update

Preview the prospective Markdown from exact find-and-replace edits without mutating the template.

Remove Template Collaborator

Remove a collaborator's permission to edit a template.

Resend Sign Request

Resend a signature request to one signer.

Send Draft Contract

Send an existing draft to its signers.

Update Contract Content

Apply exact Markdown find-and-replace edits to a contract.

Update Contract Placeholder Fields

Update selected placeholder replacements on an unsigned contract.

Update Contract Signer

Update selected contact, delivery, authentication, or redirect details for a signer without resending the contract.

Update Template

Update a template's title and/or labels without changing its Markdown content.

Update Template Content

Apply exact Markdown find-and-replace edits to a template.

Withdraw Contract

Irreversibly withdraw an active unsigned contract so it can no longer be signed.

FRAMEWORKS

How to build eSignatures MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use eSignatures MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use eSignatures MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use eSignatures MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use eSignatures MCP with Claude Cowork

Codex logo

Codex

Use eSignatures MCP with Codex

OpenClaw logo

OpenClaw

Use eSignatures MCP with OpenClaw

Hermes logo

Hermes

Use eSignatures MCP with Hermes

CLI logo

CLI

Use eSignatures MCP with CLI

Google ADK logo

Google ADK

Use eSignatures MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use eSignatures MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use eSignatures MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use eSignatures MCP with LlamaIndex

CrewAI logo

CrewAI

Use eSignatures MCP with CrewAI

FAQ

Frequently asked questions

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

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

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