How to integrate Polygon io MCP with Pydantic AI

This guide walks you through connecting Polygon io to Pydantic 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 through natural language commands. This guide will help you understand how to give your Pydantic 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.

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Polygon io provides powerful APIs for real-time and historical market data—covering stocks, options, forex, and crypto. Instantly access reliable financial data to power your applications or trading strategies.

60 Tools

Introduction

This guide walks you through connecting Polygon io to Pydantic 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 through natural language commands.

This guide will help you understand how to give your Pydantic 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.

Also integrate Polygon io with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Polygon io
  • How to attach an MCP Server to a Pydantic AI agent
  • How to stream responses and maintain chat history
  • How to build a simple REPL-style chat interface to test your Polygon io workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

  • Type Safety: Built on Pydantic for automatic data validation
  • MCP Support: Native support for Model Context Protocol servers
  • Streaming: Built-in support for streaming responses
  • Async First: Designed for async/await patterns

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.

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:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.
3

Install dependencies

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

  • composio connects your agent to external SaaS tools like Polygon io
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your agent to Composio's API
  • USER_ID associates your session with your account for secure tool access
  • OPENAI_API_KEY to access OpenAI LLMs
5

Import dependencies

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()
What's happening:
  • We load environment variables and import required modules
  • Composio manages connections to Polygon io
  • MCPServerStreamableHTTP connects to the Polygon io MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant
6

Create a Tool Router Session

python
async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Polygon io
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["polygon_io"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")
What's happening:
  • We're creating a Tool Router session that gives your agent access to Polygon io tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
7

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
polygon_io_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[polygon_io_mcp],
    instructions=(
        "You are a Polygon io assistant. Use Polygon io tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Polygon io endpoint
  • The agent uses GPT-5 to interpret user commands and perform Polygon io operations
  • The instructions field defines the agent's role and behavior
8

Build the chat interface

python
# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Polygon io.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()
What's happening:
  • The agent reads input from the terminal and streams its response
  • Polygon io API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns
9

Run the application

python
if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Polygon io and Pydantic AI:

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Polygon io
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["polygon_io"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    polygon_io_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[polygon_io_mcp],
        instructions=(
            "You are a Polygon io assistant. Use Polygon io tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Polygon io.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've built a Pydantic AI agent that can interact with Polygon io through Composio's Tool Router. With this setup, your agent can perform real Polygon io actions through natural language. You can extend this further by:
  • Adding other toolkits like Gmail, HubSpot, or Salesforce
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Polygon io for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.
TOOLS

Supported Tools

Every Polygon io action and event your agent gets out of the box.

Get All Tickers

Tool to retrieve a comprehensive list of supported ticker symbols across all asset classes.

Get Condition Codes

Tool to retrieve a unified list of trade and quote condition codes and their definitions.

Get Crypto EMA

Tool to calculate Exponential Moving Average (EMA) technical indicator for a crypto ticker.

Get Crypto MACD

Tool to calculate Moving Average Convergence/Divergence (MACD) technical indicator for a crypto ticker.

Get Crypto Open/Close

Tool to get the open, close, high, low, and volume for a cryptocurrency pair on a specific date.

Get Crypto RSI

Tool to calculate the Relative Strength Index (RSI) for a cryptocurrency ticker.

Get Crypto SMA

Tool to calculate Simple Moving Average (SMA) technical indicator for a cryptocurrency ticker.

Get Daily Open/Close

Tool to get the daily open, close, after-hours, and pre-market prices for a stock on a specific date.

Get Dividends

Tool to retrieve a historical record of cash dividend distributions for a given ticker.

Get Economy Inflation Indicators (Enhanced)

Tool to retrieve key indicators of realized inflation including CPI and PCE price indexes with comprehensive date filtering.

Get Exponential Moving Average

Tool to retrieve the Exponential Moving Average for a stock ticker.

Get SEC Filing

Tool to retrieve detailed information about a specific SEC filing by filing ID.

Get SEC Filing File

Tool to download a specific file from an SEC filing.

Get Forex EMA

Tool to calculate Exponential Moving Average (EMA) technical indicator for a forex pair.

Get Forex MACD

Tool to calculate Moving Average Convergence/Divergence (MACD) technical indicator for a forex pair.

Get Forex Real-Time Currency Conversion

Tool to convert amounts between currency pairs using real-time forex rates.

Get Forex RSI

Tool to calculate the Relative Strength Index (RSI) technical indicator for a forex pair.

Get Forex SMA

Tool to calculate Simple Moving Average (SMA) technical indicator for a forex pair.

Get Futures Quotes

Tool to get real-time quote information for futures contracts with bid/ask prices, sizes, and timestamps.

Get Grouped Daily Market Summary

Tool to retrieve daily OHLCV data for the entire market for a given date.

Get Historic Forex Ticks

Tool to get historic ticks for a currency pair on a specific date.

Get Inflation Expectations

Tool to retrieve inflation expectations data from the Federal Reserve, including market-based rates and Cleveland Fed model estimates.

Get IPO Data

Tool to retrieve comprehensive information on Initial Public Offerings (IPOs), including upcoming and historical events.

Get Labor Market Data

Tool to retrieve labor market data including unemployment rate, labor force participation rate, average hourly earnings, and job openings.

Get MACD

Tool to retrieve the Moving Average Convergence/Divergence (MACD) for a stock ticker.

Get Market Holidays

Tool to retrieve upcoming market holidays and their corresponding open/close times.

Get Market Status

Tool to retrieve the current trading status across major exchanges and currency markets.

Get News

Tool to retrieve the most recent news articles for a specified ticker.

Get Options Contract Overview

Tool to retrieve comprehensive details about a specific options contract including contract type, exercise style, expiration date, strike price, and underlying ticker.

Get Options EMA

Tool to calculate Exponential Moving Average (EMA) technical indicator for an options ticker.

Get Options MACD

Tool to calculate Moving Average Convergence/Divergence (MACD) technical indicator for an options ticker.

Get Options RSI

Tool to calculate Relative Strength Index (RSI) technical indicator for an options ticker.

Get Options SMA

Tool to calculate Simple Moving Average (SMA) technical indicator for an options ticker.

Get Related Companies

Tool to retrieve tickers related to a given ticker based on similar business or market characteristics.

Get RSI

Tool to retrieve the Relative Strength Index (RSI) for a stock ticker.

Get Simple Moving Average

Tool to retrieve the Simple Moving Average (SMA) for any ticker (stocks, forex, crypto).

Get Splits

Tool to retrieve historical stock split events for a given ticker.

Get Stocks Custom Bars

Tool to retrieve aggregated historical OHLC and volume data for a stock over custom date ranges with configurable time windows.

Get Stocks Daily Market Summary

Tool to retrieve daily OHLC, volume, and VWAP data for all U.

Get Stocks Filings Risk Factors

Tool to retrieve risk factors identified in companies' 10K filings.

Get Stocks Filings Sections

Tool to retrieve raw text content from specific sections of SEC filings (10-K, 10-Q, etc.

Get Stocks Free Float

Tool to retrieve free float data for US-listed securities showing the most recent available number of shares available for public trading and the percentage of total shares outstanding.

Get Stocks Full Market Snapshot

Tool to retrieve a comprehensive snapshot of the entire U.

Get Stocks Income Statements

Tool to retrieve comprehensive income statement data including revenue, expenses, and net income from company SEC filings.

Get Stocks Previous Day Bar

Tool to retrieve the previous trading day's open, high, low, close (OHLC), and volume data for a stock ticker.

Get Stocks Risk Factor Taxonomies

Tool to retrieve the complete list of risk factor classifications used in the risk factors endpoint.

Get Stocks V1 Dividends

Tool to retrieve historical dividend payment records for US stocks with split-adjusted amounts and historical adjustment factors.

Get Short Interest Data

Tool to retrieve comprehensive FINRA short interest data that tracks the short selling metrics for securities on a specific settlement date.

Get Short Volume Data

Tool to retrieve short selling volume data for stock tickers.

Get Stocks V1 Splits

Tool to retrieve historical stock split and reverse split events for US equities with historical adjustment factors for price normalization.

Get Ticker Events

Tool to retrieve timeline of ticker change events such as symbol renaming or rebranding.

Get Ticker Overview

Tool to retrieve comprehensive details for a single ticker, including identifiers, industry, and branding assets.

Get Ticker Types

Tool to retrieve a list of all ticker types supported by Polygon.

Get Treasury Yields

Tool to retrieve daily market yields for US Treasury securities across standard maturities (1-month to 30-year).

List Exchanges

Tool to retrieve all exchanges supported by Polygon.

List Filing Files

Tool to retrieve files associated with an SEC filing by filing ID.

List SEC Filings

Tool to retrieve SEC filings from the Polygon.

List Options Contracts

Tool to list and filter options contracts by underlying ticker, type, expiration, strike, and more.

Last Quote for a Symbol

Tool to retrieve the last quote tick for a given stock symbol.

Last Trade for a Currency Pair

Tool to retrieve the last trade tick for a currency pair in the forex market.

FRAMEWORKS

How to build Polygon io MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Polygon io MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Polygon io MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Polygon io MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Polygon io MCP with Claude Cowork

Codex logo

Codex

Use Polygon io MCP with Codex

OpenClaw logo

OpenClaw

Use Polygon io MCP with OpenClaw

Hermes logo

Hermes

Use Polygon io MCP with Hermes

CLI logo

CLI

Use Polygon io MCP with CLI

Google ADK logo

Google ADK

Use Polygon io MCP with Google ADK

LangChain logo

LangChain

Use Polygon io MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Polygon io MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Polygon io MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Polygon io MCP with LlamaIndex

CrewAI logo

CrewAI

Use Polygon io MCP with CrewAI

FAQ

Frequently asked questions

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.

Yes, you can. Pydantic 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.

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.

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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Co-founder, Slashy

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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As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

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Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

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