How to integrate Dropbox sign MCP with Mastra AI

This guide walks you through connecting Dropbox sign to Mastra AI using the Composio tool router. By the end, you'll have a working Dropbox sign agent that can send nda for signature to new hire, get status of recent signature requests, download signed contract from last week through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Dropbox sign account through Composio's Dropbox sign MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Dropbox Sign is an electronic signature platform for sending, signing, and managing legally binding documents online. It streamlines business workflows by making signature collection fast, secure, and effortless.

56 Tools

Introduction

This guide walks you through connecting Dropbox sign to Mastra AI using the Composio tool router. By the end, you'll have a working Dropbox sign agent that can send nda for signature to new hire, get status of recent signature requests, download signed contract from last week through natural language commands.

This guide will help you understand how to give your Mastra AI agent real control over a Dropbox sign account through Composio's Dropbox sign MCP server.

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

Also integrate Dropbox sign with

ChatGPTOpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenCodeCursorVS CodeOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKLlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Dropbox sign tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Dropbox sign tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your Dropbox sign agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

What is the Dropbox sign MCP server, and what's possible with it?

The Dropbox sign MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Dropbox Sign account. It provides structured and secure access to your e-signature workflows, so your agent can prepare signature requests, manage documents, track signing progress, and automate agreement workflows on your behalf.

  • Automated signature requests: Have your agent create, send, and manage legally binding signature requests to one or multiple recipients, streamlining document approval processes.
  • Template-based document preparation: Let your agent generate documents from templates, pre-fill fields, and quickly send out repeat agreements without manual editing.
  • Status tracking and reminders: Ask your agent to monitor the progress of signature requests, check who has signed, and send automated reminders to outstanding signers as needed.
  • Secure document storage and retrieval: Effortlessly fetch completed, pending, or archived documents, download signed agreements, and keep your workflow organized and compliant.
  • Audit trails and activity logs: Access detailed audit trails and event histories for every document, so you can maintain compliance and always know who did what, and when.

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:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach Dropbox sign through MCP.
3

Install dependencies

bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_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
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models
5

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session
6

Create a Tool Router session for Dropbox sign

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["dropbox_sign"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Dropbox sign MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "dropbox_sign" for Dropbox sign access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
7

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the Dropbox sign toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "dropbox_sign-mastra-agent",
    instructions: "You are an AI agent with Dropbox sign tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM
9

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\n");

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

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;
  }

  messages.push({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        dropbox_sign: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and Dropbox sign toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with Dropbox sign and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({ apiKey: composioAPIKey as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["dropbox_sign"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      dropbox_sign: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "dropbox_sign-mastra-agent",
    instructions: "You are an AI agent with Dropbox sign tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

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

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { dropbox_sign: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with Dropbox sign through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows
TOOLS

Supported Tools

Every Dropbox sign action and event your agent gets out of the box.

Invite User to Team

Tool to invite a user to your Team.

Add User to Template

Tool to grant a specified account access to a template.

Bulk create embedded signature request with template

Tool to create a BulkSendJob for embedded templated signature requests.

Bulk send with template

Tool to create a BulkSendJob for templated signature requests.

Cancel Signature Request

Cancels an incomplete signature request.

Create Dropbox Sign Account

Tool to create a new Dropbox Sign account associated with a specified email address.

Create API App

Tool to create a new Dropbox Sign API App.

Create Embedded Signature Request

Tool to create an embedded signature request for signing in an iFrame.

Create Embedded Signature Request With Template

Tool to create an embedded signature request based on a template.

Create Embedded Template Draft

Tool to create an embedded template draft.

Create Embedded Unclaimed Draft with Template

Tool to create an embedded unclaimed draft using saved templates.

Create Report

Request creation of CSV report(s) for a specified date range.

Create Template

Tool to create a reusable template for document signing workflows.

Create Unclaimed Draft

Tool to create an unclaimed draft that can be claimed via a unique URL.

Delete API App

Tool to delete an API App from your Dropbox Sign account by its client_id.

Delete Fax

Tool to delete a fax from the system by its fax_id.

Delete Template

Permanently deletes a template from your Dropbox Sign account by its template_id.

Download Signature Request Files

Download files for a signature request as PDF (merged) or ZIP (individual documents).

Edit and Resend Embedded Signature Request

Tool to edit and resend an embedded signature request.

Edit and Resend Signature Request

Edits and resends an existing non-templated signature request with updated documents, signers, or settings.

Edit and Resend Unclaimed Draft

Tool to edit and resend a previously created unclaimed draft.

Edit and Resend Embedded Signature Request With Template

Tool to edit and resend an embedded signature request using templates.

Get Dropbox Sign Account

Retrieves detailed information about a Dropbox Sign account including quotas, payment status, and settings.

Get API App

Tool to retrieve information about an API App by its client ID.

Get Bulk Send Job

Tool to retrieve the status of a bulk send job.

Get Current Team Membership

Tool to get the current team membership status and details.

Get Embedded Sign URL

Retrieves an embedded signing URL for a specific signer's signature.

Get Embedded Template Edit URL

Tool to generate an edit URL for embedded template editing.

Get Available Fax Line Area Codes

Tool to retrieve available fax line area codes for a given country, state/province, and city.

Get Signature Request

Retrieves the current status and complete details of a signature request by ID.

Get Signature Request Files as Data URI

Tool to download signature request files as a base64-encoded data URI.

Get Signature Request Files as File URL

Retrieves a copy of the current documents and returns a JSON object with a URL to the file (PDFs only).

Get Team Info

Retrieves information about a Dropbox Sign team, including team name, member count, and sub-team count.

Get Template

Tool to return the specified template.

Download Template Files

Tool to download documents associated with a template.

Get Template Files as Data URI

Tool to retrieve template documents as base64-encoded data URI.

Get Template Files as File URL

Tool to retrieve a copy of template documents and return a JSON object with a URL to the file (PDFs only).

List API Apps

Tool to list API Apps.

List Bulk Send Jobs

Tool to list bulk send jobs.

List Faxes

Tool to list faxes and their properties.

List Fax Lines

Tool to list fax lines and their properties.

List Signature Requests

Tool to list signature requests.

List Sub-Teams

Lists all sub-teams belonging to a parent team with pagination support.

List Team Members

Lists all members and their roles for a specific team.

List All Teams

Lists all Dropbox Sign teams accessible to the authenticated user, including the current team and its sub-teams.

List Templates

Tool to list templates.

Generate OAuth Authorization URL

Tool to generate an OAuth authorization URL.

Release Signature Request Hold

Release a held signature request to send it to signers.

Remove User from Template

Tool to remove an account's access to a template.

Send Signature Request

Tool to create and send a new signature request with documents.

Send Request Reminder

Sends an email reminder to a signer about a pending signature request.

Update Dropbox Sign Account

Tool to update Dropbox Sign account properties and settings.

Update API App

Tool to update an existing API App in Dropbox Sign.

Update Signature Request

Updates the email address and/or name for a specific signer on a signature request.

Update Template Files

Tool to update files for an existing template.

Verify Dropbox Sign Account

Tool to verify whether a Dropbox Sign account exists for the given email.

FRAMEWORKS

How to build Dropbox sign MCP Agent with another framework

ChatGPT logo

ChatGPT

Use Dropbox sign MCP with ChatGPT

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Dropbox sign MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Dropbox sign MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Dropbox sign MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Dropbox sign MCP with Claude Cowork

Codex logo

Codex

Use Dropbox sign MCP with Codex

Cursor logo

Cursor

Use Dropbox sign MCP with Cursor

OpenClaw logo

OpenClaw

Use Dropbox sign MCP with OpenClaw

Hermes logo

Hermes

Use Dropbox sign MCP with Hermes

CLI logo

CLI

Use Dropbox sign MCP with CLI

Google ADK logo

Google ADK

Use Dropbox sign MCP with Google ADK

LangChain logo

LangChain

Use Dropbox sign MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Dropbox sign MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Dropbox sign MCP with LlamaIndex

CrewAI logo

CrewAI

Use Dropbox sign MCP with CrewAI

OpenCode logo

OpenCode

Use Dropbox sign MCP with OpenCode

VS Code logo

VS Code

Use Dropbox sign MCP with VS Code

FAQ

Frequently asked questions

With a standalone Dropbox sign MCP server, the agents and LLMs can only access a fixed set of Dropbox sign tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Dropbox sign and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Mastra AI 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 Dropbox sign tools.

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

Start with Dropbox sign.It takes 30 seconds.

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A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

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