model = ai.get_model("anthropic/claude-sonnet-4")

uv add "ai[openai]"
uv add "ai[anthropic]"

messages = [
    ai.system_message("Be concise."),
    ai.user_message("Write a haiku about rain."),
]

import asyncio

import ai


@ai.tool
async def get_weather(city: str) -> str:
    """Get the weather for a city."""
    return "Sunny"


async def main() -> None:
    model = ai.get_model("anthropic/claude-sonnet-4")
    agent = ai.Agent(tools=[get_weather])
    messages = [
        ai.system_message("Use tools when useful."),
        ai.user_message("What is the weather in San Francisco?"),
    ]

    async with agent.run(model, messages) as run:
        async for event in run:
            if isinstance(event, ai.events.TextDelta):
                print(event.chunk, end="", flush=True)

    answer = run.output
    history = run.messages


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

async with ai.stream(model, messages) as stream:
    async for event in stream:
        if isinstance(event, ai.events.TextDelta):
            print(event.chunk, end="", flush=True)

answer = stream.output
messages.append(stream.message)