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.

Task	Page	Local notes
Provider clients, options, discovery	basics/providers.md	—
Structured output, complex streams	basics/streaming.md	—
Buffered language-model calls	basics/streaming.md	—
Images, video, speech, embeddings, transcription, reranking	basics/model-operations.md	—
Events and serialization	basics/messages-and-events.md	—
Advanced tools, streaming, aggregation	basics/tools.md	streaming-tools.md
Advanced agent behavior	basics/agents.md	—
Deterministic model and agent tests	basics/testing.md	—
Subagents and multi-agent	basics/subagents-and-multi-agent.md	streaming-tools.md
Custom agent loops	basics/custom-loops.md	custom-loops.md
Approvals and hooks	basics/human-in-the-loop.md	—
Serverless resume	basics/human-in-the-loop.md	serverless.md
Durable execution	basics/durable-execution.md	durable.md
Telemetry and tracing	basics/telemetry.md	—
AI SDK UI backends	basics/ai-sdk-ui.md	ui.md
Custom providers	basics/providers.md	custom-provider.md

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