How to integrate Polygon io MCP with Mastra AI

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Introduction

This guide walks you through connecting Polygon io to Mastra AI using the Composio tool router. By the end, you'll have a working Polygon io agent that can get daily summary for aapl stock, retrieve latest news on tsla ticker, check if nyse market is open now, calculate rsi for msft over 14 days through natural language commands.

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

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

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

The Polygon 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 Polygon io account. It provides structured and secure access to real-time and historical financial market data, so your agent can pull ticker lists, fetch stock summaries, analyze technical indicators, and surface news updates on your behalf.

  • Comprehensive ticker discovery and lookup: Instantly retrieve detailed lists of supported stock, forex, crypto, and option tickers to power your trading dashboards or research tools.
  • Daily summary and technical analysis: Ask your agent to fetch daily price summaries, calculate exponential moving averages, MACD, or RSI for any supported ticker and timeframe.
  • Financial events and dividend insights: Pull up historical dividend distributions, keep tabs on scheduled market holidays, and plan trading activities around real exchange calendars.
  • Up-to-date market status monitoring: Have your agent check real-time market open/close statuses and trading conditions across multiple exchanges and asset classes.
  • Automated news aggregation for securities: Let your agent gather the latest news articles, sentiment analysis, and headlines for specific tickers, helping you stay informed with minimal effort.

Supported Tools & Triggers

Tools
Get All TickersTool to retrieve a comprehensive list of supported ticker symbols across all asset classes.
Get Condition CodesTool to retrieve a unified list of trade and quote condition codes and their definitions.
Get Daily Ticker SummaryTool to retrieve daily aggregate summary for a specific stock ticker.
Get DividendsTool to retrieve a historical record of cash dividend distributions for a given ticker.
Get Exponential Moving AverageTool to retrieve the exponential moving average for a stock ticker.
Get MACDTool to retrieve the moving average convergence/divergence (macd) for a stock ticker.
Get Market HolidaysTool to retrieve upcoming market holidays and their corresponding open/close times.
Get Market StatusTool to retrieve the current trading status across major exchanges and currency markets.
Get NewsTool to retrieve the most recent news articles for a specified ticker.
Get RSITool to retrieve the relative strength index (rsi) for a stock ticker.
Get Simple Moving AverageTool to retrieve the simple moving average (sma) for a forex ticker.
Get SplitsTool to retrieve historical stock split events for a given ticker.
Get Ticker OverviewTool to retrieve comprehensive details for a single ticker, including identifiers, industry, and branding assets.
Get Ticker TypesTool to retrieve a list of all ticker types supported by polygon.

What is the Composio tool router, and how does it fit here?

What is Tool Router?

Composio's Tool Router 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 Tool Router

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Tool Router works

The Tool Router 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 Polygon io 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 Polygon io

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

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

Create the Mastra agent

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

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "polygon_io-mastra-agent",
    instructions: "You are an AI agent with Polygon io 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: { polygon_io: 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 Polygon io 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 Polygon io MCP Agent with another framework

OpenAI Agents SDK

OpenAI Agents SDK

Use Polygon io MCP with OpenAI Agents SDK

Claude Agent SDK

Claude Agent SDK

Use Polygon io MCP with Claude Agent SDK

Google ADK

Google ADK

Use Polygon io MCP with Google ADK

LangChain

LangChain

Use Polygon io MCP with LangChain

Vercel AI SDK

Vercel AI SDK

Use Polygon io MCP with Vercel AI SDK

LlamaIndex

LlamaIndex

Use Polygon io MCP with LlamaIndex

CrewAI

CrewAI

Use Polygon io MCP with CrewAI

FAQ

What are the differences in Tool Router MCP and Polygon io MCP?

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

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

Yes, absolutely. You can configure which Polygon 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.

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 Polygon io data and credentials are handled as safely as possible.

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