How to integrate Documenso MCP with Mastra AI

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Introduction

This guide walks you through connecting Documenso to Mastra AI using the Composio tool router. By the end, you'll have a working Documenso agent that can send a contract to client for signature, download the latest signed nda document, list all templates for onboarding paperwork through natural language commands.

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

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

Also integrate Documenso with

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 Documenso tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Documenso 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 Documenso 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 Documenso MCP server, and what's possible with it?

The Documenso MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Documenso account. It provides structured and secure access to your electronic signature workflows, so your agent can create documents, distribute them for signing, manage templates, and download signed files automatically on your behalf.

  • Automated document creation and duplication: Prompt your agent to generate new documents or make exact copies of existing ones for rapid workflow setup.
  • Seamless document distribution for signatures: Let your agent send documents to one or more recipients, kicking off secure e-signature flows without manual intervention.
  • Template management and retrieval: Ask your agent to list, fetch, or delete document templates, keeping your signing processes organized and up-to-date.
  • Download and access signed documents: Have your agent retrieve finalized, signed PDFs automatically for seamless archiving or sharing.
  • Streamlined document organization: Direct your agent to move documents between personal and team spaces, or remove unnecessary fields to keep everything tidy and current.

Supported Tools & Triggers

Tools
Create Document BetaTool to create a new document using the beta endpoint that returns a presigned URL for file upload.
Create Document FieldTool to create a single field for a document.
Create Document Fields (Bulk)Tool to create multiple fields on a document in a single operation.
Create Document RecipientTool to create a single recipient for a document.
Create Document Recipients BulkTool to create multiple recipients for a document at once.
Create Embedding Presign Token V2 BetaCreate a presign token for Documenso embedded authoring sessions.
Create EnvelopeTool to create a new envelope in Documenso.
Create Envelope AttachmentCreate a new attachment for an envelope in Documenso.
Create Envelope Items BulkTool to create multiple items for an envelope with optional file attachments.
Create Envelope Recipients BulkTool to create multiple recipients for an envelope in bulk.
Create FolderCreate a new folder in Documenso to organize documents or templates.
Create Template BetaTool to create a new template using the beta endpoint that returns a presigned URL for file upload.
Create Template FieldTool to create a single field for a template.
Create Template Fields (Bulk)Tool to create multiple fields on a template in a single operation.
Create Template RecipientTool to create a single recipient for a template.
Create Template Recipients BulkTool to create multiple recipients for a template at once.
Delete DocumentTool to delete a document.
Delete Document AttachmentTool to delete an attachment from a document.
Delete Document FieldTool to delete a single document field by ID.
Delete Document FieldsTool to delete one or more fields from a document.
Delete Document RecipientTool to delete a recipient from a document.
Delete EnvelopeTool to permanently delete an envelope.
Delete Envelope AttachmentTool to delete an attachment from an envelope.
Delete Envelope FieldTool to delete a field from an envelope.
Delete Envelope ItemTool to delete an item from an envelope.
Delete Envelope RecipientTool to delete a recipient from an envelope.
Delete FolderTool to permanently delete a folder.
Delete TemplatePermanently delete a template by its ID.
Delete Template Direct LinkDelete a direct link for a template.
Delete Template RecipientTool to delete a recipient from a template.
Delete Template V2Tool to permanently delete a template using the v2 API.
Distribute Document V2Tool to distribute a document for signing.
Distribute EnvelopeTool to distribute an envelope to recipients for signing.
Download Envelope ItemDownload an envelope item as PDF.
Download Signed DocumentDownload a completed/signed document as PDF.
Duplicate Document V2Tool to duplicate a document.
Duplicate Envelope V2Tool to duplicate an envelope with all its settings.
Duplicate TemplateTool to duplicate a template with all its settings.
Find DocumentsFind documents based on search criteria with filtering and pagination.
Find Documents V2Retrieve a paginated list of documents with optional filtering and sorting.
Find EnvelopesTool to find envelopes based on search criteria, filters, and pagination.
Find FoldersTool to find folders based on search criteria and filters.
Find TemplatesRetrieve a paginated list of templates with optional filtering and search.
Get Document By IDRetrieve complete information about a document by its ID.
Get Document FieldTool to retrieve a document field by its ID.
Get Document RecipientTool to retrieve detailed information about a document recipient by their ID.
Get Documents By IDsRetrieve multiple documents by their IDs in a single request.
Get Envelope AttachmentTool to find all attachments for a specific envelope.
Get Envelope Audit LogTool to retrieve audit logs for an envelope.
Get Envelope By IDRetrieve complete information about an envelope by its ID.
Get Envelope FieldTool to fetch an envelope field by ID.
Get Envelope RecipientTool to retrieve detailed information about an envelope recipient by their ID.
Get Envelopes By IDsTool to retrieve multiple envelopes by their IDs.
Get Template By IDRetrieve complete information about a template by its ID.
Get Template FieldTool to fetch a template field by ID.
Get Template RecipientTool to retrieve detailed information about a template recipient by their ID.
Get Templates By IDsRetrieve multiple templates by their IDs in a single request.
List TemplatesTool to list templates.
Move Document V2Tool to move a document to a team.
Redistribute Document V2Re-send signing request emails to specified recipients of a document.
Redistribute EnvelopeTool to redistribute an envelope to recipients who have not actioned it.
Remove Team Member V1Remove a member from a Documenso team.
Update Document AttachmentTool to update an existing document attachment.
Update Document FieldTool to update a single document field's properties in Documenso v2 API.
Update Document Fields BulkTool to update multiple document fields in a single operation.
Update Document Recipient V2Tool to update a document recipient using the v2 API.
Update Document V2Update document properties like title, visibility, and signing settings.
Update EnvelopeUpdate envelope properties like title, visibility, and signing settings.
Update Envelope AttachmentTool to update an existing envelope attachment.
Update Envelope Fields BulkTool to update multiple envelope fields in a single request.
Update Envelope Items BulkTool to update multiple envelope items in a single request.
Update FolderUpdate properties of an existing folder including name, pinned status, parent folder, and visibility.
Update TemplateUpdate template properties like title, visibility, and signing settings.
Update Template Fields BulkTool to update multiple template fields in a single operation.
Update Template RecipientTool to update a template recipient.
Update Template Recipients BulkTool to update multiple template recipients in a single API call.
Use Template (v2-beta)Tool to create a document from a template.

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

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

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 Documenso through MCP.

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

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

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

Create a Tool Router session for Documenso

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

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

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 Documenso toolkit

Create the Mastra agent

typescript
const agent = new Agent({
    name: "documenso-mastra-agent",
    instructions: "You are an AI agent with Documenso 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

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: {
        documenso: 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 Documenso 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 Documenso 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: ["documenso"],
  });

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "documenso-mastra-agent",
    instructions: "You are an AI agent with Documenso 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: { documenso: 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 Documenso 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

How to build Documenso MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Documenso MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Documenso MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Documenso MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Documenso MCP with Claude Cowork

Codex logo

Codex

Use Documenso MCP with Codex

OpenClaw logo

OpenClaw

Use Documenso MCP with OpenClaw

Hermes logo

Hermes

Use Documenso MCP with Hermes

CLI logo

CLI

Use Documenso MCP with CLI

Google ADK logo

Google ADK

Use Documenso MCP with Google ADK

LangChain logo

LangChain

Use Documenso MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Documenso MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Documenso MCP with LlamaIndex

CrewAI logo

CrewAI

Use Documenso MCP with CrewAI

FAQ

What are the differences in Tool Router MCP and Documenso MCP?

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

Can I use Tool Router MCP with Mastra AI?

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 Documenso tools.

Can I manage the permissions and scopes for Documenso while using Tool Router?

Yes, absolutely. You can configure which Documenso 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.

How safe is my data with Composio Tool Router?

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 Documenso data and credentials are handled as safely as possible.

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