version: "1.0.1" name: ai description: AI SDK for Python (the ai package). Use when writing Python that calls LLMs or builds agents — model calls, streaming, tool calling, subagents, human-in-the-loop approvals, durable/serverless execution, telemetry, AI SDK UI chat backends, custom providers. metadata: sdk-version: "0.4.0"

AI SDK for Python

Package: ai. Requires Python 3.12+. Install with uv add ai.

Unprefixed model IDs use AI Gateway and AI_GATEWAY_API_KEY. Direct providers use provider:model, their API key, and an extra:

uv add "ai[openai]"     # OPENAI_API_KEY,    ai.get_model("openai:gpt-5")
uv add "ai[anthropic]"  # ANTHROPIC_API_KEY, ai.get_model("anthropic:claude-sonnet-4")

Basic use

Use ai.stream for one model call without Python tool execution:

import ai
model = ai.get_model("anthropic/claude-sonnet-4")
messages = [
    ai.system_message("Be concise."),
    ai.user_message("Write a haiku about rain."),
]
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
message = stream.message

Use ai.Agent for a loop that executes Python tools and manages history:

@ai.tool
async def get_weather(city: str) -> str:
    """Get the weather for a city."""
    return "Sunny"
agent = ai.Agent(tools=[get_weather])
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

These examples are sufficient for basic model calls, messages, tools, and agents.

Advanced work

For an advanced task, fetch its page under https://ai-python.dev/docs/ and read the listed local notes before writing code.

For exact APIs, use reference.md and the relevant reference/*.md page.