How to integrate Oksign MCP with LangChain

This guide walks you through connecting Oksign to LangChain using the Composio tool router. By the end, you'll have a working Oksign agent that can send signature request for nda document, list all pending signature requests, download signed contract for order #12345 through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Oksign account through Composio's Oksign MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Oksign is an online platform for signing contracts, purchase orders, and forms. It makes digital signatures fast, simple, and legally binding.

17 Tools

Introduction

This guide walks you through connecting Oksign to LangChain using the Composio tool router. By the end, you'll have a working Oksign agent that can send signature request for nda document, list all pending signature requests, download signed contract for order #12345 through natural language commands.

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

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

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

The Oksign MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Oksign account. It provides structured and secure access so your agent can perform Oksign operations on your behalf.

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 Oksign 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 Oksign 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: ['oksign']
    }
);

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

Configure the agent with the MCP URL

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

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

Remove Briefcase

Tool to remove a previously created briefcase from OKSign platform.

Retrieve Briefcase Information

Tool to retrieve a previously uploaded briefcase tokeninfo for consultation.

Remove Contacts

Tool to remove specified contacts from the account's contact list.

Retrieve Contacts

Tool to retrieve the list of contacts stored in the account.

Upload Contacts

Tool to insert or update contact information in the account's contact list.

Retrieve Account Credits

Tool to retrieve account credit balance and storage information.

Check Document Exists

Tool to check if a signed or unsigned document still exists on the OKSign platform.

Remove Document

Tool to remove a signed or unsigned document from the OKSign platform.

Upload Document

Tool to upload a PDF or Word document to OKSign platform for completion and/or signing.

Create Editor Express Session

Tool to invoke the OKSign Editor Express for modifying documents and form descriptors.

Upload Form Descriptor

Tool to upload form descriptor defining signature fields and other field types to a document.

Get Active Documents

Tool to retrieve all active document IDs and properties from OKsign account.

Retrieve Linked Document List

Tool to retrieve the list of linked signed or source document IDs related to a specific document.

Upload Notifications

Tool to upload notifications defining email(s) and/or SMS(es) to be sent to signer(s) with signing links.

Update Organization Token Info

Tool to update organizational token information and settings for the account.

Remove SignExpress Token

Tool to remove a previously uploaded SignExpress tokeninfo JSONObject from the OKSign platform.

Retrieve Users

Tool to retrieve the list of users associated with the OkSign account.

FRAMEWORKS

How to build Oksign MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Oksign MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Oksign MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Oksign MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Oksign MCP with Claude Cowork

Codex logo

Codex

Use Oksign MCP with Codex

OpenClaw logo

OpenClaw

Use Oksign MCP with OpenClaw

Hermes logo

Hermes

Use Oksign MCP with Hermes

CLI logo

CLI

Use Oksign MCP with CLI

Google ADK logo

Google ADK

Use Oksign MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Oksign MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Oksign MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Oksign MCP with LlamaIndex

CrewAI logo

CrewAI

Use Oksign MCP with CrewAI

FAQ

Frequently asked questions

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

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

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