How to integrate AccuWeather MCP with Pydantic AI

This guide walks you through connecting AccuWeather to Pydantic AI using the Composio tool router. By the end, you'll have a working AccuWeather agent that can fetch current conditions, get hourly forecasts, retrieve your weather alerts, and report minute-by-minute precipitation through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a AccuWeather account through Composio's AccuWeather MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

AccuWeather logoAccuWeather
Api Key

AccuWeather is a global weather service providing current conditions, forecasts, MinuteCast precipitation, alerts, and lightning data. Use it for fast, localized forecasts and real-time weather alerts.

41 Tools

Introduction

This guide walks you through connecting AccuWeather to Pydantic AI using the Composio tool router. By the end, you'll have a working AccuWeather agent that can fetch current conditions, get hourly forecasts, retrieve your weather alerts, and report minute-by-minute precipitation through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a AccuWeather account through Composio's AccuWeather 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:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for AccuWeather
  • 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 AccuWeather 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 AccuWeather MCP server, and what's possible with it?

The AccuWeather MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your AccuWeather account. It provides structured and secure access to global weather conditions, forecasts, alerts, precipitation updates, and storm data, so your agent can check current weather, plan around forecasts, monitor alerts, assess precipitation, and track tropical storms on your behalf.

  • Current conditions and forecasts: Have your agent check current conditions and retrieve hourly or daily forecasts for cities and other locations worldwide.
  • Weather alerts and alarms: Let the agent monitor active government weather alerts and threshold-based alarms for locations you care about.
  • Minute-by-minute rain and lightning: Direct your agent to assess near-term precipitation, forecast lightning probability, or review recent lightning strikes around chosen coordinates.
  • Tropical storm tracking: Instruct your agent to find active tropical storms and review their latest positions, observed paths, forecast tracks, intensity, and status.
  • Local weather context: Have your agent find locations, explore nearby cities, review lifestyle indices, or retrieve recent radar and satellite imagery for trip and activity planning.

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 AccuWeather
  • 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 AccuWeather
  • MCPServerStreamableHTTP connects to the AccuWeather 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 AccuWeather
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["accu_weather"],
    )
    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 AccuWeather 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
accu_weather_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[accu_weather_mcp],
    instructions=(
        "You are a AccuWeather assistant. Use AccuWeather tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the AccuWeather endpoint
  • The agent uses GPT-5 to interpret user commands and perform AccuWeather 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 AccuWeather.\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
  • AccuWeather 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 AccuWeather 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 AccuWeather
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["accu_weather"],
    )
    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
    accu_weather_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[accu_weather_mcp],
        instructions=(
            "You are a AccuWeather assistant. Use AccuWeather 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 AccuWeather.\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 AccuWeather through Composio's Tool Router. With this setup, your agent can perform real AccuWeather 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 + AccuWeather 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 AccuWeather action and event your agent gets out of the box.

Autocomplete Locations

Return location-name suggestions for all locations, cities, or points of interest, optionally restricted to a country.

Get Administrative Area

Return one administrative area by country and administrative-area codes.

Get Country

Return one country by AccuWeather region and country codes.

Get Current Conditions

Return current weather observations for an AccuWeather location key, optionally including extended details and weather photos.

Get Daily Forecast

Return a 1, 5, 7, 10, or 15-day forecast for a location key.

Get Daily Indices

Return 1, 5, 10, or 15-day lifestyle-index forecasts for all indices, one group, or one index at an AccuWeather location.

Get Historical Current Conditions

Return the past 6 or 24 hours of current-condition observations for an AccuWeather location key.

Get Hourly Forecast

Return a 1, 12, 24, 72, or 120-hour forecast for an AccuWeather location key.

Get Index

Return metadata for one AccuWeather lifestyle index.

Get Index Group

Return the lifestyle indices belonging to one AccuWeather index group.

Get Lightning Forecast

Return forecast lightning probabilities for latitude/longitude coordinates.

Get Location

Return full location metadata for an AccuWeather location key.

Get MinuteCast Forecast

Return minute-by-minute precipitation conditions for latitude/longitude coordinates.

Get Radar and Satellite Imagery

Return recent radar and satellite image metadata and URLs for an AccuWeather location at a selected resolution.

Get Region

Return one AccuWeather region by region code.

Get Translation Group

Return translated strings for one AccuWeather translation group.

Get Tropical Storm Current Position

Return the latest observed position of a government-issued tropical storm.

List Active Tropical Storms

Return active government-issued tropical storms globally, by basin, or by basin and government storm ID.

List Administrative Areas

Return administrative areas globally or within a country, one provider page at a time.

List Countries

Return countries globally or within a specific AccuWeather region, one provider page at a time.

List Index Groups

Return lifestyle-index groups and their identifiers.

List Indices

Return all supported lifestyle indices and their identifiers.

List MinuteCast Color Codes

Return full or simplified color-code metadata used in MinuteCast precipitation output.

List Neighboring Cities

Return cities near an AccuWeather location key.

List Recent Lightning Strikes

Return recent lightning strikes within 1 to 60 miles of latitude/longitude coordinates as a GeoJSON FeatureCollection.

List Regions

Return AccuWeather geographic regions and their codes.

List Supported Languages

Return AccuWeather-supported languages with numeric IDs and language codes.

List Top Cities

Return top-ranked AccuWeather cities globally or within one region.

List Top City Conditions

Return current weather conditions for a requested number of globally ranked cities.

List Translation Groups

Return available AccuWeather translation groups and their identifiers.

List Tropical Storm Forecasts

Return forecast positions and intensity for a government-issued tropical storm.

List Tropical Storm Positions

Return the observed position history of a government-issued tropical storm.

List Tropical Storms by Year

Return government-issued tropical storms for a year, optionally filtered by basin and government storm ID.

List Tropical Storm Statuses

Return government-issued tropical storm status categories and wind-speed definitions globally or for one basin.

List Weather Alarms

Return threshold-based weather alarms for the next 1, 5, 10, or 15 days at an AccuWeather location.

List Weather Alerts

Return active government-issued weather alerts for a location key.

Resolve Language Identifier

Convert an AccuWeather language code to its numeric ID or a numeric language ID to its code.

Search Administrative Areas

Search administrative areas by required non-empty name text and optional country and administrative-area code filters, one 25-result provider page at a time.

Search City by IP Address

Resolve an IPv4 or IPv6 address to an AccuWeather city location.

Search Locations

Search cities, general locations, postal codes, or points of interest by text and optional geographic filters.

Search Locations by Coordinates

Find the nearest general location, city, or point of interest to latitude/longitude coordinates.

FAQ

Frequently asked questions

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

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

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