How to integrate Elorus MCP with Mastra AI

This guide walks you through connecting Elorus to Mastra AI using the Composio tool router. By the end, you'll have a working Elorus agent that can create a new invoice for acme corp, list all unpaid bills from last month, email latest invoice to a specific contact through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a Elorus account through Composio's Elorus MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Elorus is an online invoicing and time-tracking software for freelancers and small businesses. Easily manage finances, bill clients, and track work in one place.

13 Tools

Introduction

This guide walks you through connecting Elorus to Mastra AI using the Composio tool router. By the end, you'll have a working Elorus agent that can create a new invoice for acme corp, list all unpaid bills from last month, email latest invoice to a specific contact through natural language commands.

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

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

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

The Elorus MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Elorus account. It provides structured and secure access to your invoicing, billing, and time-tracking tools, so your agent can perform actions like creating invoices, managing contacts, tracking estimates, and sending billing communications on your behalf.

  • Automated invoice creation and delivery: Instruct your agent to generate new invoices, fill in all necessary details, and instantly email them to clients or contacts with just a prompt.
  • Comprehensive contact management: Ask your agent to fetch, list, and organize your business contacts, so you can easily keep your client database up to date or find specific clients in seconds.
  • Dynamic bills and expenses tracking: Let your agent retrieve and manage lists of bills and expenses, helping you stay on top of accounts payable and overall financial health.
  • Flexible product and service catalog management: Direct your agent to create new products or services, update details, or fetch lists of items for invoicing and inventory purposes.
  • Estimates and credit notes retrieval: Have your agent pull up estimates or credit notes with filters for date, contact, or status—ideal for monitoring ongoing deals and financial adjustments.

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 Elorus 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 Elorus

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

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

Create the Mastra agent

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

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

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

Create Invoice

Creates a new invoice or receipt in Elorus.

CREATE_PRODUCT

Create a new product or service in Elorus.

Email Invoice

Tool to email an existing invoice to specified contacts.

Get Bills

Retrieve a paginated list of bills (expenses/purchases) from Elorus.

Get Contacts

Tool to retrieve a list of contacts.

Get Credit Notes

Tool to retrieve a list of credit notes.

Get Email Templates

Tool to retrieve a list of email templates.

Get Estimates

Tool to retrieve a list of estimates.

Get Invoices

Retrieves a paginated list of invoices from Elorus with flexible filtering options.

Get Products

Tool to retrieve a list of products/services with optional filtering, sorting, and pagination.

Get Taxes

Tool to retrieve a list of taxes.

Get Templates

Retrieves document templates used for formatting invoices, estimates, credit notes, and other business documents in Elorus.

Update Contact

Update an existing contact in Elorus by ID.

FRAMEWORKS

How to build Elorus MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Elorus MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Elorus MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Elorus MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Elorus MCP with Claude Cowork

Codex logo

Codex

Use Elorus MCP with Codex

OpenClaw logo

OpenClaw

Use Elorus MCP with OpenClaw

Hermes logo

Hermes

Use Elorus MCP with Hermes

CLI logo

CLI

Use Elorus MCP with CLI

Google ADK logo

Google ADK

Use Elorus MCP with Google ADK

LangChain logo

LangChain

Use Elorus MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Elorus MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Elorus MCP with LlamaIndex

CrewAI logo

CrewAI

Use Elorus MCP with CrewAI

FAQ

Frequently asked questions

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

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

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