How to integrate Signwell MCP with LangChain

This guide walks you through connecting Signwell to LangChain using the Composio tool router. By the end, you'll have a working Signwell agent that can send nda document for signature to client, list all pending documents awaiting signatures, delete a document that was sent by mistake through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Signwell account through Composio's Signwell MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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SignWell is an electronic signature platform for creating and sending legally binding documents. It streamlines contract signing and automates workflows for faster turnaround.

12 Tools

Introduction

This guide walks you through connecting Signwell to LangChain using the Composio tool router. By the end, you'll have a working Signwell agent that can send nda document for signature to client, list all pending documents awaiting signatures, delete a document that was sent by mistake through natural language commands.

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

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

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

The Signwell MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Signwell account. It provides structured and secure access to your document signing workflow, so your agent can perform actions like sending signature requests, managing documents, handling webhooks, and retrieving account info on your behalf.

  • Automated document creation and sending: Have your agent generate new documents and instantly send them out for e-signature—no manual uploads or email juggling required.
  • Real-time document status retrieval: Let your agent fetch the latest status and details of any document, so you always know who has signed and what’s still pending.
  • Bulk send management: Effortlessly list and track large batches of signature requests, helping you stay organized when sending documents to multiple recipients.
  • Webhook automation and monitoring: Register or remove webhooks so your agent can monitor document events and respond instantly to completed, signed, or cancelled documents.
  • Credential and account validation: Quickly check and verify your Signwell account details and API credentials directly through your agent.

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 Signwell 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 Signwell 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: ['signwell']
    }
);

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

Configure the agent with the MCP URL

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

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

Create Document

Tool to create and optionally send a new document for signing.

Create Document from Template

Tool to create and optionally send a new document for signing from a template.

Create Webhook

Tool to register a webhook callback URL.

Delete Document

Tool to delete a document (and cancel signing if in progress).

Delete Webhook

Deletes a registered webhook by its ID.

Get Credentials

Retrieve account information for the authenticated API key.

Get Document

Tool to return a document and all associated document data.

List Bulk Sends

Tool to list all Bulk Sends.

List Webhooks

Tool to list all registered webhooks.

Send Reminder

Tool to send a reminder email to recipients that have not signed yet.

Update and Send Document

Tool to update a draft document and send it to recipients for signing.

Update Template

Tool to update an existing template in SignWell.

FRAMEWORKS

How to build Signwell MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Signwell MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Signwell MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Signwell MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Signwell MCP with Claude Cowork

Codex logo

Codex

Use Signwell MCP with Codex

OpenClaw logo

OpenClaw

Use Signwell MCP with OpenClaw

Hermes logo

Hermes

Use Signwell MCP with Hermes

CLI logo

CLI

Use Signwell MCP with CLI

Google ADK logo

Google ADK

Use Signwell MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Signwell MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Signwell MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Signwell MCP with LlamaIndex

CrewAI logo

CrewAI

Use Signwell MCP with CrewAI

FAQ

Frequently asked questions

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

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

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