pydantic--pydantic-ai/docs/examples/weather-agent.md

Example of Pydantic AI with multiple tools which the LLM needs to call in turn to answer a question.

Demonstrates:

• tools
• agent dependencies
• streaming text responses
• Building a Gradio UI for the agent

In this case the idea is a "weather" agent — the user can ask for the weather in multiple locations, the agent will use the get_lat_lng tool to get the latitude and longitude of the locations, then use the get_weather tool to get the weather for those locations.

Running the Example

To run this example properly, you might want to add two extra API keys (Note if either key is missing, the code will fall back to dummy data, so they're not required):

• A weather API key from tomorrow.io set via WEATHER_API_KEY
• A geocoding API key from geocode.maps.co set via GEO_API_KEY

With dependencies installed and environment variables set, run:

python/uv-run -m pydantic_ai_examples.weather_agent

Example Code

snippet {path="/examples/pydantic_ai_examples/weather_agent.py"}

Running the UI

You can build multi-turn chat applications for your agent with Gradio, a framework for building AI web applications entirely in python. Gradio comes with built-in chat components and agent support so the entire UI will be implemented in a single python file!

Here's what the UI looks like for the weather agent:

{{ video('c549d8d8827ded15f326f998e428e6c3', 6) }}

pip install gradio>=6.7.0
python/uv-run -m pydantic_ai_examples.weather_agent_gradio

UI Code

snippet {path="/examples/pydantic_ai_examples/weather_agent_gradio.py"}