How to integrate ActiveMerge MCP with Mastra AI

This guide walks you through connecting ActiveMerge to Mastra AI using the Composio tool router. By the end, you'll have a working ActiveMerge agent that can generate invoices from saved templates, merge contract files for client signature, store signed ndas in project folders through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a ActiveMerge account through Composio's ActiveMerge MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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ActiveMerge is a document automation platform for generating documents, images, merged files, and e-signature workflows. It helps teams turn templates and stored files into finished, shareable documents faster.

13 Tools

Introduction

This guide walks you through connecting ActiveMerge to Mastra AI using the Composio tool router. By the end, you'll have a working ActiveMerge agent that can generate invoices from saved templates, merge contract files for client signature, store signed ndas in project folders through natural language commands.

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

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

Also integrate ActiveMerge with

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

The ActiveMerge MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your ActiveMerge account. It provides structured and secure access to your templates, workflows, generation jobs, credits, and stored files, so your agent can generate documents, create images, run template workflows, track generation progress, and manage generated files on your behalf.

  • Template-based document generation: Have your agent review available document templates and their required placeholders, then generate documents using your case-sensitive data.
  • Automated image creation: Let the agent inspect image templates, create images from your records, and check each generation job for progress, errors, and completed output.
  • Multi-document workflows: Direct your agent to find available workflows, collect their required placeholders, and generate documents for every template in a chosen workflow.
  • Generation tracking and credit checks: Instruct your agent to check remaining credits before starting work, then review document generation history and job status.
  • Generated file management: Have your agent browse stored files, save completed document outputs to permanent storage, and prepare stored files for download.

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 ActiveMerge 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 ActiveMerge

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

  const composioMCPUrl = session.mcp.url;
  console.log("ActiveMerge MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "active_merge" for ActiveMerge 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 ActiveMerge toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "active_merge-mastra-agent",
    instructions: "You are an AI agent with ActiveMerge 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: {
        active_merge: 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 ActiveMerge 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 ActiveMerge 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: ["active_merge"],
  });

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "active_merge-mastra-agent",
    instructions: "You are an AI agent with ActiveMerge 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: { active_merge: 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 ActiveMerge 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 ActiveMerge action and event your agent gets out of the box.

Generate Document

Start asynchronous document generation from a template and case-sensitive placeholder data.

Generate Images

Start an asynchronous image-generation job from inline JSON records.

Generate Workflow Documents

Generate documents for every template in an ActiveMerge workflow using case-sensitive placeholder data.

Get Credits

Get total, used, remaining, plan, and prepaid ActiveMerge credits before running credit-consuming generation tools.

Get Document Generations

Get one document-generation job by ID, or list and filter generation history when no job ID is supplied.

Get Document Template Placeholders

Return the case-sensitive placeholder names required by one document template.

Get File Download URL

Create a temporary download URL for a file in ActiveMerge cloud storage.

Get Image Generation

Get an image-generation job's progress, credit usage, errors, and temporary ZIP download URL when complete.

Get Image Templates

List image templates and basic placeholders, or get complete dimensions, positions, defaults, and styles for one template when template_id is supplied.

Get Workflows

List available ActiveMerge workflows, or return the case-sensitive placeholders for one workflow when workflow_id is supplied.

List Document Templates

List document templates available to the connected ActiveMerge account, including the unique template IDs needed for placeholder lookup and generation.

List Stored Files

List the immediate files and folders at the ActiveMerge cloud-storage root, or directly inside parent_folder_id when supplied.

Save Generated Files

Save non-expired output from a completed document-generation job to permanent ActiveMerge cloud storage.

FRAMEWORKS

How to build ActiveMerge MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use ActiveMerge MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use ActiveMerge MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use ActiveMerge MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use ActiveMerge MCP with Claude Cowork

Codex logo

Codex

Use ActiveMerge MCP with Codex

OpenClaw logo

OpenClaw

Use ActiveMerge MCP with OpenClaw

Hermes logo

Hermes

Use ActiveMerge MCP with Hermes

CLI logo

CLI

Use ActiveMerge MCP with CLI

Google ADK logo

Google ADK

Use ActiveMerge MCP with Google ADK

LangChain logo

LangChain

Use ActiveMerge MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use ActiveMerge MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use ActiveMerge MCP with LlamaIndex

CrewAI logo

CrewAI

Use ActiveMerge MCP with CrewAI

FAQ

Frequently asked questions

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

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

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