How to integrate Esignatures io MCP with Claude Agent SDK

This guide walks you through connecting Esignatures io to the Claude Agent SDK 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 Claude Agent SDK 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 the Claude Agent SDK 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 Claude Agent SDK 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 CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Get and set up your Claude/Anthropic and Composio API keys
  • Install the necessary dependencies
  • Initialize Composio and create a Tool Router session for Esignatures io
  • Configure an AI agent that can use Esignatures io as a tool
  • Run a live chat session where you can ask the agent to perform Esignatures io operations

What is Claude Agent SDK?

The Claude Agent SDK is Anthropic's official framework for building AI agents powered by Claude. It provides a streamlined interface for creating agents with MCP tool support and conversation management.

Key features include:

  • Native MCP Support: Built-in support for Model Context Protocol servers
  • Permission Modes: Control tool execution permissions
  • Streaming Responses: Real-time response streaming for interactive applications
  • Context Manager: Clean async context management for sessions

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 step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Composio API Key and Claude/Anthropic API Key
  • Primary know-how of Claude Agents SDK
  • A Esignatures io account
  • Some knowledge of Python
2

Getting API Keys for Claude/Anthropic and Composio

Claude/Anthropic API Key
  • Go to the Anthropic Console and create an API key. You'll need credits to use the models.
  • 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 @anthropic-ai/claude-agent-sdk @composio/core dotenv

Install the Composio SDK and the Claude Agents SDK.

What's happening:

  • @composio/core provides Composio integration for Anthropic
  • @anthropic-ai/claude-agent-sdk is the core agent framework
  • dotenv/config loads environment variables
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
ANTHROPIC_API_KEY=your_anthropic_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates with Composio
  • USER_ID identifies the user for session management
  • ANTHROPIC_API_KEY authenticates with Anthropic/Claude
5

Import dependencies

import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

dotenv.config();
What's happening:
  • We're importing all necessary libraries including the Claude Agent SDK and Composio
  • The dotenv.config() function loads environment variables from your .env file
  • This setup prepares the foundation for connecting Claude with Esignatures io functionality
6

Create a Composio instance and Tool Router session

async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

  const composio = new Composio({ apiKey: COMPOSIO_API_KEY });

  // Create Tool Router session for Esignatures io
  const session = await composio.create(USER_ID, {
    toolkits: ['esignatures_io'],
  });
  const mcpUrl = session?.mcp.url;
What's happening:
  • The function checks for the required COMPOSIO_API_KEY environment variable
  • We're creating a Composio instance using our API key
  • The create method creates a Tool Router session for Esignatures io
  • The returned url is the MCP server URL that your agent will use
7

Configure Claude Agent with MCP

const options: Options = {
  permissionMode: 'bypassPermissions',
  mcpServers: {
    composio: {
      type: 'http',
      url: mcpUrl,
      headers: { 'x-api-key': COMPOSIO_API_KEY }
    }
  },
  systemPrompt: 'You are a helpful assistant with access to Esignatures io tools via Composio.',
  maxTurns: 10,
};
What's happening:
  • We're configuring the Claude Agent options with the MCP server URL
  • permissionMode: 'bypassPermissions' allows the agent to execute operations without asking for permission each time
  • The system prompt instructs the agent that it has access to Esignatures io
  • maxTurns: 10 limits the conversation length to prevent excessive API usage
8

Create client and start chat loop

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
  });

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}
What's happening:
  • The readline interface is created to handle user input and output
  • The query function is used to send the user's input to the agent
  • The chat loop continues until the user types 'exit' or 'quit'
9

Run the application

try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}
What's happening:
  • The chat function is the entry point for the application
  • The try-catch block is used to handle any errors that occur

Complete Code

Here's the complete code to get you started with Esignatures io and Claude Agent SDK:

import 'dotenv/config';
import readline from 'node:readline';
import { Composio } from '@composio/core';
import { query, type Options } from "@anthropic-ai/claude-agent-sdk";

async function chat() {
  const { COMPOSIO_API_KEY, USER_ID } = process.env;
  if (!COMPOSIO_API_KEY || !USER_ID) {
    throw new Error('COMPOSIO_API_KEY and USER_ID required in .env');
  }

  const composio = new Composio({ apiKey: COMPOSIO_API_KEY });
  const session = await composio.create(USER_ID, {
    toolkits: ['esignatures_io']
  });
  const mcp_url = session?.mcp.url;

  const options: Options = {
    permissionMode: 'bypassPermissions',
    mcpServers: {
      composio: {
        type: 'http',
        url: mcp_url,
        headers: { 'x-api-key': COMPOSIO_API_KEY }
      }
    },
    systemPrompt: 'You are a helpful assistant with access to Esignatures io tools via Composio.',
    maxTurns: 10,
  };

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
  });

  console.log('\nChat started. Type "exit" to quit.\n');

  let isProcessing = false;

  async function ask(prompt: string) {
    isProcessing = true;
    rl.pause();

    process.stdout.write('Claude is thinking...');
    const stream = query({ prompt, options });

    let firstChunk = true;
    for await (const msg of stream) {
      const content = (msg as any).message?.content || (msg as any).content;
      if (Array.isArray(content)) {
        for (const block of content) {
          if (block.type === 'text' && block.text) {
            if (firstChunk) {
              process.stdout.write('\r\x1b[K');
              process.stdout.write('Claude: ');
              firstChunk = false;
            }
            process.stdout.write(block.text);
          }
        }
      }
    }
    process.stdout.write('\n\n');

    isProcessing = false;
    rl.resume();
    rl.prompt();
  }

  rl.on('line', async (line) => {
    if (isProcessing) return;

    const input = line.trim();
    if (input === 'exit') {
      rl.close();
      process.exit(0);
    }
    if (input) await ask(input);
    else rl.prompt();
  });

  await ask('What can you help me with?');
}

try {
  await chat();
} catch (error) {
  console.error(error);
  process.exit(1);
}

Conclusion

You've successfully built a Claude Agent SDK agent that can interact with Esignatures io through Composio's Tool Router.

Key features:

  • Native MCP support through Claude's agent framework
  • Streaming responses for real-time interaction
  • Permission bypass for smooth automated workflows
You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.
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 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

LangChain logo

LangChain

Use Esignatures io MCP with LangChain

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. Claude Agent SDK 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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